gpg

GPG(1) GNU Privacy Guard 2.2 GPG(1)

NAME
gpg - OpenPGP encryption and signing tool

SYNOPSIS
gpg [--homedir dir] [--options file] [options] command [args]

DESCRIPTION
gpg is the OpenPGP part of the GNU Privacy Guard (GnuPG). It is a tool
to provide digital encryption and signing services using the OpenPGP
standard. gpg features complete key management and all the bells and
whistles you would expect from a full OpenPGP implementation.

There are two main versions of GnuPG: GnuPG 1.x and GnuPG 2.x. GnuPG
2.x supports modern encryption algorithms and thus should be preferred
over GnuPG 1.x. You only need to use GnuPG 1.x if your platform
doesn't support GnuPG 2.x, or you need support for some features that
GnuPG 2.x has deprecated, e.g., decrypting data created with PGP-2
keys.

If you are looking for version 1 of GnuPG, you may find that version
installed under the name gpg1.

RETURN VALUE
The program returns 0 if everything was fine, 1 if at least a signature
was bad, and other error codes for fatal errors.

WARNINGS
Use a *good* password for your user account and a *good* passphrase to
protect your secret key. This passphrase is the weakest part of the
whole system. Programs to do dictionary attacks on your secret keyring
are very easy to write and so you should protect your "~/.gnupg/" di-
rectory very well.

Keep in mind that, if this program is used over a network (telnet), it
is *very* easy to spy out your passphrase!

If you are going to verify detached signatures, make sure that the pro-
gram knows about it; either give both filenames on the command line or
use '-' to specify STDIN.

For scripted or other unattended use of gpg make sure to use the ma-
chine-parseable interface and not the default interface which is in-
tended for direct use by humans. The machine-parseable interface pro-
vides a stable and well documented API independent of the locale or fu-
ture changes of gpg. To enable this interface use the options --with-
colons and --status-fd. For certain operations the option --command-fd
may come handy too. See this man page and the file 'DETAILS' for the
specification of the interface. Note that the GnuPG ``info'' pages as
well as the PDF version of the GnuPG manual features a chapter on unat-
tended use of GnuPG. As an alternative the library GPGME can be used
as a high-level abstraction on top of that interface.

INTEROPERABILITY
GnuPG tries to be a very flexible implementation of the OpenPGP stan-
dard. In particular, GnuPG implements many of the optional parts of the
standard, such as the SHA-512 hash, and the ZLIB and BZIP2 compression
algorithms. It is important to be aware that not all OpenPGP programs
implement these optional algorithms and that by forcing their use via
the --cipher-algo, --digest-algo, --cert-digest-algo, or --compress-
algo options in GnuPG, it is possible to create a perfectly valid
OpenPGP message, but one that cannot be read by the intended recipient.

There are dozens of variations of OpenPGP programs available, and each
supports a slightly different subset of these optional algorithms. For
example, until recently, no (unhacked) version of PGP supported the
BLOWFISH cipher algorithm. A message using BLOWFISH simply could not be
read by a PGP user. By default, GnuPG uses the standard OpenPGP prefer-
ences system that will always do the right thing and create messages
that are usable by all recipients, regardless of which OpenPGP program
they use. Only override this safe default if you really know what you
are doing.

If you absolutely must override the safe default, or if the preferences
on a given key are invalid for some reason, you are far better off us-
ing the --pgp6, --pgp7, or --pgp8 options. These options are safe as
they do not force any particular algorithms in violation of OpenPGP,
but rather reduce the available algorithms to a "PGP-safe" list.

COMMANDS
Commands are not distinguished from options except for the fact that
only one command is allowed. Generally speaking, irrelevant options
are silently ignored, and may not be checked for correctness.

gpg may be run with no commands. In this case it will print a warning
perform a reasonable action depending on the type of file it is given
as input (an encrypted message is decrypted, a signature is verified, a
file containing keys is listed, etc.).

If you run into any problems, please add the option --verbose to the
invocation to see more diagnostics.

Commands not specific to the function

--version
Print the program version and licensing information. Note that
you cannot abbreviate this command.

--help
-h Print a usage message summarizing the most useful command-line
options. Note that you cannot arbitrarily abbreviate this com-
mand (though you can use its short form -h).

--warranty
Print warranty information.

--dump-options
Print a list of all available options and commands. Note that
you cannot abbreviate this command.

Commands to select the type of operation

--sign
-s Sign a message. This command may be combined with --encrypt (to
sign and encrypt a message), --symmetric (to sign and symmetri-
cally encrypt a message), or both --encrypt and --symmetric (to
sign and encrypt a message that can be decrypted using a secret
key or a passphrase). The signing key is chosen by default or
can be set explicitly using the --local-user and --default-key
options.

--clear-sign
--clearsign
Make a cleartext signature. The content in a cleartext signa-
ture is readable without any special software. OpenPGP software
is only needed to verify the signature. cleartext signatures
may modify end-of-line whitespace for platform independence and
are not intended to be reversible. The signing key is chosen by
default or can be set explicitly using the --local-user and
--default-key options.

--detach-sign
-b Make a detached signature.

--encrypt
-e Encrypt data to one or more public keys. This command may be
combined with --sign (to sign and encrypt a message), --symmet-
ric (to encrypt a message that can be decrypted using a secret
key or a passphrase), or --sign and --symmetric together (for a
signed message that can be decrypted using a secret key or a
passphrase). --recipient and related options specify which pub-
lic keys to use for encryption.

--symmetric
-c Encrypt with a symmetric cipher using a passphrase. The default
symmetric cipher used is AES-128, but may be chosen with the
--cipher-algo option. This command may be combined with --sign
(for a signed and symmetrically encrypted message), --encrypt
(for a message that may be decrypted via a secret key or a
passphrase), or --sign and --encrypt together (for a signed mes-
sage that may be decrypted via a secret key or a passphrase).
gpg caches the passphrase used for symmetric encryption so that
a decrypt operation may not require that the user needs to enter
the passphrase. The option --no-symkey-cache can be used to
disable this feature.

--store
Store only (make a simple literal data packet).

--decrypt
-d Decrypt the file given on the command line (or STDIN if no file
is specified) and write it to STDOUT (or the file specified with
--output). If the decrypted file is signed, the signature is
also verified. This command differs from the default operation,
as it never writes to the filename which is included in the file
and it rejects files that don't begin with an encrypted message.

--verify
Assume that the first argument is a signed file and verify it
without generating any output. With no arguments, the signature
packet is read from STDIN. If only one argument is given, the
specified file is expected to include a complete signature.

With more than one argument, the first argument should specify a
file with a detached signature and the remaining files should
contain the signed data. To read the signed data from STDIN, use
'-' as the second filename. For security reasons, a detached
signature will not read the signed material from STDIN if not
explicitly specified.

Note: If the option --batch is not used, gpg may assume that a
single argument is a file with a detached signature, and it will
try to find a matching data file by stripping certain suffixes.
Using this historical feature to verify a detached signature is
strongly discouraged; you should always specify the data file
explicitly.

Note: When verifying a cleartext signature, gpg verifies only
what makes up the cleartext signed data and not any extra data
outside of the cleartext signature or the header lines directly
following the dash marker line. The option --output may be used
to write out the actual signed data, but there are other pit-
falls with this format as well. It is suggested to avoid clear-
text signatures in favor of detached signatures.

Note: Sometimes the use of the gpgv tool is easier than using
the full-fledged gpg with this option. gpgv is designed to com-
pare signed data against a list of trusted keys and returns with
success only for a good signature. It has its own manual page.

--multifile
This modifies certain other commands to accept multiple files
for processing on the command line or read from STDIN with each
filename on a separate line. This allows for many files to be
processed at once. --multifile may currently be used along with
--verify, --encrypt, and --decrypt. Note that --multifile --ver-
ify may not be used with detached signatures.

--verify-files
Identical to --multifile --verify.

--encrypt-files
Identical to --multifile --encrypt.

--decrypt-files
Identical to --multifile --decrypt.

--list-keys
-k
--list-public-keys
List the specified keys. If no keys are specified, then all
keys from the configured public keyrings are listed.

Never use the output of this command in scripts or other pro-
grams. The output is intended only for humans and its format is
likely to change. The --with-colons option emits the output in
a stable, machine-parseable format, which is intended for use by
scripts and other programs.

--list-secret-keys
-K List the specified secret keys. If no keys are specified, then
all known secret keys are listed. A # after the initial tags
sec or ssb means that the secret key or subkey is currently not
usable. We also say that this key has been taken offline (for
example, a primary key can be taken offline by exporting the key
using the command --export-secret-subkeys). A > after these
tags indicate that the key is stored on a smartcard. See also
--list-keys.

--check-signatures
--check-sigs
Same as --list-keys, but the key signatures are verified and
listed too. Note that for performance reasons the revocation
status of a signing key is not shown. This command has the same
effect as using --list-keys with --with-sig-check.

The status of the verification is indicated by a flag directly
following the "sig" tag (and thus before the flags described be-
low. A "!" indicates that the signature has been successfully
verified, a "-" denotes a bad signature and a "%" is used if an
error occurred while checking the signature (e.g. a non sup-
ported algorithm). Signatures where the public key is not
available are not listed; to see their keyids the command
--list-sigs can be used.

For each signature listed, there are several flags in between
the signature status flag and keyid. These flags give addi-
tional information about each key signature. From left to
right, they are the numbers 1-3 for certificate check level (see
--ask-cert-level), "L" for a local or non-exportable signature
(see --lsign-key), "R" for a nonRevocable signature (see the
--edit-key command "nrsign"), "P" for a signature that contains
a policy URL (see --cert-policy-url), "N" for a signature that
contains a notation (see --cert-notation), "X" for an eXpired
signature (see --ask-cert-expire), and the numbers 1-9 or "T"
for 10 and above to indicate trust signature levels (see the
--edit-key command "tsign").

--locate-keys
--locate-external-keys
Locate the keys given as arguments. This command basically uses
the same algorithm as used when locating keys for encryption or
signing and may thus be used to see what keys gpg might use. In
particular external methods as defined by --auto-key-locate may
be used to locate a key. Only public keys are listed. The
variant --locate-external-keys does not consider a locally ex-
isting key and can thus be used to force the refresh of a key
via the defined external methods.

--show-keys
This commands takes OpenPGP keys as input and prints information
about them in the same way the command --list-keys does for lo-
cally stored key. In addition the list options show-unusable-
uids, show-unusable-subkeys, show-notations and show-policy-urls
are also enabled. As usual for automated processing, this com-
mand should be combined with the option --with-colons.

--fingerprint
List all keys (or the specified ones) along with their finger-
prints. This is the same output as --list-keys but with the ad-
ditional output of a line with the fingerprint. May also be com-
bined with --check-signatures. If this command is given twice,
the fingerprints of all secondary keys are listed too. This
command also forces pretty printing of fingerprints if the keyid
format has been set to "none".

--list-packets
List only the sequence of packets. This command is only useful
for debugging. When used with option --verbose the actual MPI
values are dumped and not only their lengths. Note that the
output of this command may change with new releases.

--edit-card
--card-edit
Present a menu to work with a smartcard. The subcommand "help"
provides an overview on available commands. For a detailed de-
scription, please see the Card HOWTO at https://gnupg.org/docu-
mentation/howtos.html#GnuPG-cardHOWTO .

--card-status
Show the content of the smart card.

--change-pin
Present a menu to allow changing the PIN of a smartcard. This
functionality is also available as the subcommand "passwd" with
the --edit-card command.

--delete-keys name
Remove key from the public keyring. In batch mode either --yes
is required or the key must be specified by fingerprint. This is
a safeguard against accidental deletion of multiple keys. If
the exclamation mark syntax is used with the fingerprint of a
subkey only that subkey is deleted; if the exclamation mark is
used with the fingerprint of the primary key the entire public
key is deleted.

--delete-secret-keys name
Remove key from the secret keyring. In batch mode the key must
be specified by fingerprint. The option --yes can be used to
advice gpg-agent not to request a confirmation. This extra pre-
caution is done because gpg can't be sure that the secret key
(as controlled by gpg-agent) is only used for the given OpenPGP
public key. If the exclamation mark syntax is used with the
fingerprint of a subkey only the secret part of that subkey is
deleted; if the exclamation mark is used with the fingerprint of
the primary key only the secret part of the primary key is
deleted.

--delete-secret-and-public-key name
Same as --delete-key, but if a secret key exists, it will be re-
moved first. In batch mode the key must be specified by finger-
print. The option --yes can be used to advice gpg-agent not to
request a confirmation.

--export
Either export all keys from all keyrings (default keyrings and
those registered via option --keyring), or if at least one name
is given, those of the given name. The exported keys are written
to STDOUT or to the file given with option --output. Use to-
gether with --armor to mail those keys.

--send-keys keyIDs
Similar to --export but sends the keys to a keyserver. Finger-
prints may be used instead of key IDs. Don't send your complete
keyring to a keyserver --- select only those keys which are new
or changed by you. If no keyIDs are given, gpg does nothing.

--export-secret-keys
--export-secret-subkeys
Same as --export, but exports the secret keys instead. The ex-
ported keys are written to STDOUT or to the file given with op-
tion --output. This command is often used along with the option
--armor to allow for easy printing of the key for paper backup;
however the external tool paperkey does a better job of creating
backups on paper. Note that exporting a secret key can be a se-
curity risk if the exported keys are sent over an insecure chan-
nel.

The second form of the command has the special property to ren-
der the secret part of the primary key useless; this is a GNU
extension to OpenPGP and other implementations can not be ex-
pected to successfully import such a key. Its intended use is
in generating a full key with an additional signing subkey on a
dedicated machine. This command then exports the key without
the primary key to the main machine.

GnuPG may ask you to enter the passphrase for the key. This is
required, because the internal protection method of the secret
key is different from the one specified by the OpenPGP protocol.

--export-ssh-key
This command is used to export a key in the OpenSSH public key
format. It requires the specification of one key by the usual
means and exports the latest valid subkey which has an authenti-
cation capability to STDOUT or to the file given with option
--output. That output can directly be added to ssh's 'autho-
rized_key' file.

By specifying the key to export using a key ID or a fingerprint
suffixed with an exclamation mark (!), a specific subkey or the
primary key can be exported. This does not even require that
the key has the authentication capability flag set.

--import
--fast-import
Import/merge keys. This adds the given keys to the keyring. The
fast version is currently just a synonym.

There are a few other options which control how this command
works. Most notable here is the --import-options merge-only op-
tion which does not insert new keys but does only the merging of
new signatures, user-IDs and subkeys.

--receive-keys keyIDs
--recv-keys keyIDs
Import the keys with the given keyIDs from a keyserver.

--refresh-keys
Request updates from a keyserver for keys that already exist on
the local keyring. This is useful for updating a key with the
latest signatures, user IDs, etc. Calling this with no arguments
will refresh the entire keyring.

--search-keys names
Search the keyserver for the given names. Multiple names given
here will be joined together to create the search string for the
keyserver. Note that keyservers search for names in a different
and simpler way than gpg does. The best choice is to use a mail
address. Due to data privacy reasons keyservers may even not
even allow searching by user id or mail address and thus may
only return results when being used with the --recv-key command
to search by key fingerprint or keyid.

--fetch-keys URIs
Retrieve keys located at the specified URIs. Note that different
installations of GnuPG may support different protocols (HTTP,
FTP, LDAP, etc.). When using HTTPS the system provided root
certificates are used by this command.

--update-trustdb
Do trust database maintenance. This command iterates over all
keys and builds the Web of Trust. This is an interactive command
because it may have to ask for the "ownertrust" values for keys.
The user has to give an estimation of how far she trusts the
owner of the displayed key to correctly certify (sign) other
keys. GnuPG only asks for the ownertrust value if it has not yet
been assigned to a key. Using the --edit-key menu, the assigned
value can be changed at any time.

--check-trustdb
Do trust database maintenance without user interaction. From
time to time the trust database must be updated so that expired
keys or signatures and the resulting changes in the Web of Trust
can be tracked. Normally, GnuPG will calculate when this is re-
quired and do it automatically unless --no-auto-check-trustdb is
set. This command can be used to force a trust database check at
any time. The processing is identical to that of --update-
trustdb but it skips keys with a not yet defined "ownertrust".

For use with cron jobs, this command can be used together with
--batch in which case the trust database check is done only if a
check is needed. To force a run even in batch mode add the op-
tion --yes.

--export-ownertrust
Send the ownertrust values to STDOUT. This is useful for backup
purposes as these values are the only ones which can't be re-
created from a corrupted trustdb. Example:
gpg --export-ownertrust > otrust.txt

--import-ownertrust
Update the trustdb with the ownertrust values stored in files
(or STDIN if not given); existing values will be overwritten.
In case of a severely damaged trustdb and if you have a recent
backup of the ownertrust values (e.g. in the file 'otrust.txt'),
you may re-create the trustdb using these commands:
cd ~/.gnupg
rm trustdb.gpg
gpg --import-ownertrust < otrust.txt

--rebuild-keydb-caches
When updating from version 1.0.6 to 1.0.7 this command should be
used to create signature caches in the keyring. It might be
handy in other situations too.

--print-md algo
--print-mds
Print message digest of algorithm algo for all given files or
STDIN. With the second form (or a deprecated "*" for algo) di-
gests for all available algorithms are printed.

--gen-random 0|1|2 count
Emit count random bytes of the given quality level 0, 1 or 2. If
count is not given or zero, an endless sequence of random bytes
will be emitted. If used with --armor the output will be base64
encoded. PLEASE, don't use this command unless you know what
you are doing; it may remove precious entropy from the system!

--gen-prime mode bits
Use the source, Luke :-). The output format is subject to change
with ant release.

--enarmor
--dearmor
Pack or unpack an arbitrary input into/from an OpenPGP ASCII ar-
mor. This is a GnuPG extension to OpenPGP and in general not
very useful.

--tofu-policy {auto|good|unknown|bad|ask} keys
Set the TOFU policy for all the bindings associated with the
specified keys. For more information about the meaning of the
policies, see: [trust-model-tofu]. The keys may be specified
either by their fingerprint (preferred) or their keyid.

How to manage your keys

This section explains the main commands for key management.

--quick-generate-key user-id [algo [usage [expire]]]
--quick-gen-key
This is a simple command to generate a standard key with one
user id. In contrast to --generate-key the key is generated di-
rectly without the need to answer a bunch of prompts. Unless
the option --yes is given, the key creation will be canceled if
the given user id already exists in the keyring.

If invoked directly on the console without any special options
an answer to a ``Continue?'' style confirmation prompt is re-
quired. In case the user id already exists in the keyring a
second prompt to force the creation of the key will show up.

If algo or usage are given, only the primary key is created and
no prompts are shown. To specify an expiration date but still
create a primary and subkey use ``default'' or ``future-de-
fault'' for algo and ``default'' for usage. For a description
of these optional arguments see the command --quick-add-key.
The usage accepts also the value ``cert'' which can be used to
create a certification only primary key; the default is to a
create certification and signing key.

The expire argument can be used to specify an expiration date
for the key. Several formats are supported; commonly the ISO
formats ``YYYY-MM-DD'' or ``YYYYMMDDThhmmss'' are used. To make
the key expire in N seconds, N days, N weeks, N months, or N
years use ``seconds=N'', ``Nd'', ``Nw'', ``Nm'', or ``Ny'' re-
spectively. Not specifying a value, or using ``-'' results in a
key expiring in a reasonable default interval. The values
``never'', ``none'' can be used for no expiration date.

If this command is used with --batch, --pinentry-mode has been
set to loopback, and one of the passphrase options
(--passphrase, --passphrase-fd, or passphrase-file) is used, the
supplied passphrase is used for the new key and the agent does
not ask for it. To create a key without any protection
--passphrase '' may be used.

To create an OpenPGP key from the keys available on the cur-
rently inserted smartcard, the special string ``card'' can be
used for algo. If the card features an encryption and a signing
key, gpg will figure them out and creates an OpenPGP key con-
sisting of the usual primary key and one subkey. This works
only with certain smartcards. Note that the interactive --full-
gen-key command allows to do the same but with greater flexibil-
ity in the selection of the smartcard keys.

Note that it is possible to create a primary key and a subkey
using non-default algorithms by using ``default'' and changing
the default parameters using the option --default-new-key-algo.

--quick-set-expire fpr expire [*|subfprs]
With two arguments given, directly set the expiration time of
the primary key identified by fpr to expire. To remove the ex-
piration time 0 can be used. With three arguments and the third
given as an asterisk, the expiration time of all non-revoked and
not yet expired subkeys are set to expire. With more than two
arguments and a list of fingerprints given for subfprs, all non-
revoked subkeys matching these fingerprints are set to expire.

--quick-add-key fpr [algo [usage [expire]]]
Directly add a subkey to the key identified by the fingerprint
fpr. Without the optional arguments an encryption subkey is
added. If any of the arguments are given a more specific subkey
is added.

algo may be any of the supported algorithms or curve names given
in the format as used by key listings. To use the default algo-
rithm the string ``default'' or ``-'' can be used. Supported
algorithms are ``rsa'', ``dsa'', ``elg'', ``ed25519'',
``cv25519'', and other ECC curves. For example the string
``rsa'' adds an RSA key with the default key length; a string
``rsa4096'' requests that the key length is 4096 bits. The
string ``future-default'' is an alias for the algorithm which
will likely be used as default algorithm in future versions of
gpg. To list the supported ECC curves the command gpg --with-
colons --list-config curve can be used.

Depending on the given algo the subkey may either be an encryp-
tion subkey or a signing subkey. If an algorithm is capable of
signing and encryption and such a subkey is desired, a usage
string must be given. This string is either ``default'' or
``-'' to keep the default or a comma delimited list (or space
delimited list) of keywords: ``sign'' for a signing subkey,
``auth'' for an authentication subkey, and ``encr'' for an en-
cryption subkey (``encrypt'' can be used as alias for ``encr'').
The valid combinations depend on the algorithm.

--generate-key
--gen-key
Generate a new key pair using the current default parameters.
This is the standard command to create a new key. In addition
to the key a revocation certificate is created and stored in the
'openpgp-revocs.d' directory below the GnuPG home directory.

--full-generate-key
--full-gen-key
Generate a new key pair with dialogs for all options. This is
an extended version of --generate-key.

There is also a feature which allows you to create keys in batch
mode. See the manual section ``Unattended key generation'' on
how to use this.

--generate-revocation name
--gen-revoke name
Generate a revocation certificate for the complete key. To only
revoke a subkey or a key signature, use the --edit command.

This command merely creates the revocation certificate so that
it can be used to revoke the key if that is ever needed. To ac-
tually revoke a key the created revocation certificate needs to
be merged with the key to revoke. This is done by importing the
revocation certificate using the --import command. Then the re-
voked key needs to be published, which is best done by sending
the key to a keyserver (command --send-key) and by exporting
(--export) it to a file which is then send to frequent communi-
cation partners.

--generate-designated-revocation name
--desig-revoke name
Generate a designated revocation certificate for a key. This al-
lows a user (with the permission of the keyholder) to revoke
someone else's key.

--edit-key
Present a menu which enables you to do most of the key manage-
ment related tasks. It expects the specification of a key on
the command line.

uid n Toggle selection of user ID or photographic user ID with
index n. Use * to select all and 0 to deselect all.

key n Toggle selection of subkey with index n or key ID n. Use
* to select all and 0 to deselect all.

sign Make a signature on key of user name. If the key is not
yet signed by the default user (or the users given with
-u), the program displays the information of the key
again, together with its fingerprint and asks whether it
should be signed. This question is repeated for all users
specified with -u.

lsign Same as "sign" but the signature is marked as non-ex-
portable and will therefore never be used by others. This
may be used to make keys valid only in the local environ-
ment.

nrsign Same as "sign" but the signature is marked as non-revoca-
ble and can therefore never be revoked.

tsign Make a trust signature. This is a signature that combines
the notions of certification (like a regular signature),
and trust (like the "trust" command). It is generally
only useful in distinct communities or groups. For more
information please read the sections ``Trust Signature''
and ``Regular Expression'' in RFC-4880.

Note that "l" (for local / non-exportable), "nr" (for non-revo-
cable, and "t" (for trust) may be freely mixed and prefixed to
"sign" to create a signature of any type desired.

If the option --only-sign-text-ids is specified, then any non-text
based user ids (e.g., photo IDs) will not be selected for signing.

delsig Delete a signature. Note that it is not possible to re-
tract a signature, once it has been send to the public
(i.e. to a keyserver). In that case you better use
revsig.

revsig Revoke a signature. For every signature which has been
generated by one of the secret keys, GnuPG asks whether a
revocation certificate should be generated.

check Check the signatures on all selected user IDs. With the
extra option selfsig only self-signatures are shown.

adduid Create an additional user ID.

addphoto
Create a photographic user ID. This will prompt for a
JPEG file that will be embedded into the user ID. Note
that a very large JPEG will make for a very large key.
Also note that some programs will display your JPEG un-
changed (GnuPG), and some programs will scale it to fit
in a dialog box (PGP).

showphoto
Display the selected photographic user ID.

deluid Delete a user ID or photographic user ID. Note that it
is not possible to retract a user id, once it has been
send to the public (i.e. to a keyserver). In that case
you better use revuid.

revuid Revoke a user ID or photographic user ID.

primary
Flag the current user id as the primary one, removes the
primary user id flag from all other user ids and sets the
timestamp of all affected self-signatures one second
ahead. Note that setting a photo user ID as primary makes
it primary over other photo user IDs, and setting a regu-
lar user ID as primary makes it primary over other regu-
lar user IDs.

keyserver
Set a preferred keyserver for the specified user ID(s).
This allows other users to know where you prefer they get
your key from. See --keyserver-options honor-keyserver-
url for more on how this works. Setting a value of
"none" removes an existing preferred keyserver.

notation
Set a name=value notation for the specified user ID(s).
See --cert-notation for more on how this works. Setting a
value of "none" removes all notations, setting a notation
prefixed with a minus sign (-) removes that notation, and
setting a notation name (without the =value) prefixed
with a minus sign removes all notations with that name.

pref List preferences from the selected user ID. This shows
the actual preferences, without including any implied
preferences.

showpref
More verbose preferences listing for the selected user
ID. This shows the preferences in effect by including the
implied preferences of 3DES (cipher), SHA-1 (digest), and
Uncompressed (compression) if they are not already in-
cluded in the preference list. In addition, the preferred
keyserver and signature notations (if any) are shown.

setpref string
Set the list of user ID preferences to string for all (or
just the selected) user IDs. Calling setpref with no ar-
guments sets the preference list to the default (either
built-in or set via --default-preference-list), and call-
ing setpref with "none" as the argument sets an empty
preference list. Use gpg --version to get a list of
available algorithms. Note that while you can change the
preferences on an attribute user ID (aka "photo ID"),
GnuPG does not select keys via attribute user IDs so
these preferences will not be used by GnuPG.

When setting preferences, you should list the algorithms
in the order which you'd like to see them used by someone
else when encrypting a message to your key. If you don't
include 3DES, it will be automatically added at the end.
Note that there are many factors that go into choosing an
algorithm (for example, your key may not be the only re-
cipient), and so the remote OpenPGP application being
used to send to you may or may not follow your exact cho-
sen order for a given message. It will, however, only
choose an algorithm that is present on the preference
list of every recipient key. See also the INTEROPERABIL-
ITY WITH OTHER OPENPGP PROGRAMS section below.

addkey Add a subkey to this key.

addcardkey
Generate a subkey on a card and add it to this key.

keytocard
Transfer the selected secret subkey (or the primary key
if no subkey has been selected) to a smartcard. The se-
cret key in the keyring will be replaced by a stub if the
key could be stored successfully on the card and you use
the save command later. Only certain key types may be
transferred to the card. A sub menu allows you to select
on what card to store the key. Note that it is not possi-
ble to get that key back from the card - if the card gets
broken your secret key will be lost unless you have a
backup somewhere.

bkuptocard file
Restore the given file to a card. This command may be
used to restore a backup key (as generated during card
initialization) to a new card. In almost all cases this
will be the encryption key. You should use this command
only with the corresponding public key and make sure that
the file given as argument is indeed the backup to re-
store. You should then select 2 to restore as encryption
key. You will first be asked to enter the passphrase of
the backup key and then for the Admin PIN of the card.

delkey Remove a subkey (secondary key). Note that it is not pos-
sible to retract a subkey, once it has been send to the
public (i.e. to a keyserver). In that case you better
use revkey. Also note that this only deletes the public
part of a key.

revkey Revoke a subkey.

expire Change the key or subkey expiration time. If a subkey is
selected, the expiration time of this subkey will be
changed. With no selection, the key expiration of the
primary key is changed.

trust Change the owner trust value for the key. This updates
the trust-db immediately and no save is required.

disable
enable Disable or enable an entire key. A disabled key can not
normally be used for encryption.

addrevoker
Add a designated revoker to the key. This takes one op-
tional argument: "sensitive". If a designated revoker is
marked as sensitive, it will not be exported by default
(see export-options).

passwd Change the passphrase of the secret key.

toggle This is dummy command which exists only for backward com-
patibility.

clean Compact (by removing all signatures except the selfsig)
any user ID that is no longer usable (e.g. revoked, or
expired). Then, remove any signatures that are not usable
by the trust calculations. Specifically, this removes
any signature that does not validate, any signature that
is superseded by a later signature, revoked signatures,
and signatures issued by keys that are not present on the
keyring.

minimize
Make the key as small as possible. This removes all sig-
natures from each user ID except for the most recent
self-signature.

change-usage
Change the usage flags (capabilities) of the primary key
or of subkeys. These usage flags (e.g. Certify, Sign,
Authenticate, Encrypt) are set during key creation.
Sometimes it is useful to have the opportunity to change
them (for example to add Authenticate) after they have
been created. Please take care when doing this; the al-
lowed usage flags depend on the key algorithm.

cross-certify
Add cross-certification signatures to signing subkeys
that may not currently have them. Cross-certification
signatures protect against a subtle attack against sign-
ing subkeys. See --require-cross-certification. All new
keys generated have this signature by default, so this
command is only useful to bring older keys up to date.

save Save all changes to the keyrings and quit.

quit Quit the program without updating the keyrings.

The listing shows you the key with its secondary keys and all
user IDs. The primary user ID is indicated by a dot, and se-
lected keys or user IDs are indicated by an asterisk. The trust
value is displayed with the primary key: "trust" is the assigned
owner trust and "validity" is the calculated validity of the
key. Validity values are also displayed for all user IDs. For
possible values of trust, see: [trust-values].

--sign-key name
Signs a public key with your secret key. This is a shortcut ver-
sion of the subcommand "sign" from --edit.

--lsign-key name
Signs a public key with your secret key but marks it as non-ex-
portable. This is a shortcut version of the subcommand "lsign"
from --edit-key.

--quick-sign-key fpr [names]
--quick-lsign-key fpr [names]
Directly sign a key from the passphrase without any further user
interaction. The fpr must be the verified primary fingerprint
of a key in the local keyring. If no names are given, all useful
user ids are signed; with given [names] only useful user ids
matching one of theses names are signed. By default, or if a
name is prefixed with a '*', a case insensitive substring match
is used. If a name is prefixed with a '=' a case sensitive ex-
act match is done.

The command --quick-lsign-key marks the signatures as non-ex-
portable. If such a non-exportable signature already exists the
--quick-sign-key turns it into a exportable signature.

This command uses reasonable defaults and thus does not provide
the full flexibility of the "sign" subcommand from --edit-key.
Its intended use is to help unattended key signing by utilizing
a list of verified fingerprints.

--quick-add-uid user-id new-user-id
This command adds a new user id to an existing key. In contrast
to the interactive sub-command adduid of --edit-key the new-
user-id is added verbatim with only leading and trailing white
space removed, it is expected to be UTF-8 encoded, and no checks
on its form are applied.

--quick-revoke-uid user-id user-id-to-revoke
This command revokes a user ID on an existing key. It cannot be
used to revoke the last user ID on key (some non-revoked user ID
must remain), with revocation reason ``User ID is no longer
valid''. If you want to specify a different revocation reason,
or to supply supplementary revocation text, you should use the
interactive sub-command revuid of --edit-key.

--quick-set-primary-uid user-id primary-user-id
This command sets or updates the primary user ID flag on an ex-
isting key. user-id specifies the key and primary-user-id the
user ID which shall be flagged as the primary user ID. The pri-
mary user ID flag is removed from all other user ids and the
timestamp of all affected self-signatures is set one second
ahead.

--change-passphrase user-id
--passwd user-id
Change the passphrase of the secret key belonging to the cer-
tificate specified as user-id. This is a shortcut for the sub-
command passwd of the edit key menu. When using together with
the option --dry-run this will not actually change the
passphrase but check that the current passphrase is correct.

OPTIONS
gpg features a bunch of options to control the exact behaviour and to
change the default configuration.

Long options can be put in an options file (default
"~/.gnupg/gpg.conf"). Short option names will not work - for example,
"armor" is a valid option for the options file, while "a" is not. Do
not write the 2 dashes, but simply the name of the option and any re-
quired arguments. Lines with a hash ('#') as the first non-white-space
character are ignored. Commands may be put in this file too, but that
is not generally useful as the command will execute automatically with
every execution of gpg.

Please remember that option parsing stops as soon as a non-option is
encountered, you can explicitly stop parsing by using the special op-
tion --.

How to change the configuration

These options are used to change the configuration and are usually
found in the option file.

--default-key name
Use name as the default key to sign with. If this option is not
used, the default key is the first key found in the secret
keyring. Note that -u or --local-user overrides this option.
This option may be given multiple times. In this case, the last
key for which a secret key is available is used. If there is no
secret key available for any of the specified values, GnuPG will
not emit an error message but continue as if this option wasn't
given.

--default-recipient name
Use name as default recipient if option --recipient is not used
and don't ask if this is a valid one. name must be non-empty.

--default-recipient-self
Use the default key as default recipient if option --recipient
is not used and don't ask if this is a valid one. The default
key is the first one from the secret keyring or the one set with
--default-key.

--no-default-recipient
Reset --default-recipient and --default-recipient-self.

-v, --verbose
Give more information during processing. If used twice, the in-
put data is listed in detail.

--no-verbose
Reset verbose level to 0.

-q, --quiet
Try to be as quiet as possible.

--batch
--no-batch
Use batch mode. Never ask, do not allow interactive commands.
--no-batch disables this option. Note that even with a filename
given on the command line, gpg might still need to read from
STDIN (in particular if gpg figures that the input is a detached
signature and no data file has been specified). Thus if you do
not want to feed data via STDIN, you should connect STDIN to
g'/dev/null'.

It is highly recommended to use this option along with the op-
tions --status-fd and --with-colons for any unattended use of
gpg.

--no-tty
Make sure that the TTY (terminal) is never used for any output.
This option is needed in some cases because GnuPG sometimes
prints warnings to the TTY even if --batch is used.

--yes Assume "yes" on most questions.

--no Assume "no" on most questions.

--list-options parameters
This is a space or comma delimited string that gives options
used when listing keys and signatures (that is, --list-keys,
--check-signatures, --list-public-keys, --list-secret-keys, and
the --edit-key functions). Options can be prepended with a no-
(after the two dashes) to give the opposite meaning. The op-
tions are:

show-photos
Causes --list-keys, --check-signatures, --list-public-
keys, and --list-secret-keys to display any photo IDs at-
tached to the key. Defaults to no. See also --photo-
viewer. Does not work with --with-colons: see --attri-
bute-fd for the appropriate way to get photo data for
scripts and other frontends.

show-usage
Show usage information for keys and subkeys in the stan-
dard key listing. This is a list of letters indicating
the allowed usage for a key (E=encryption, S=signing,
C=certification, A=authentication). Defaults to yes.

show-policy-urls
Show policy URLs in the --check-signatures listings.
Defaults to no.

show-notations
show-std-notations
show-user-notations
Show all, IETF standard, or user-defined signature nota-
tions in the --check-signatures listings. Defaults to no.

show-keyserver-urls
Show any preferred keyserver URL in the --check-signa-
tures listings. Defaults to no.

show-uid-validity
Display the calculated validity of user IDs during key
listings. Defaults to yes.

show-unusable-uids
Show revoked and expired user IDs in key listings. De-
faults to no.

show-unusable-subkeys
Show revoked and expired subkeys in key listings. De-
faults to no.

show-keyring
Display the keyring name at the head of key listings to
show which keyring a given key resides on. Defaults to
no.

show-sig-expire
Show signature expiration dates (if any) during --check-
signatures listings. Defaults to no.

show-sig-subpackets
Include signature subpackets in the key listing. This op-
tion can take an optional argument list of the subpackets
to list. If no argument is passed, list all subpackets.
Defaults to no. This option is only meaningful when using
--with-colons along with --check-signatures.

show-only-fpr-mbox
For each user-id which has a valid mail address print
only the fingerprint followed by the mail address.

--verify-options parameters
This is a space or comma delimited string that gives options
used when verifying signatures. Options can be prepended with a
`no-' to give the opposite meaning. The options are:

show-photos
Display any photo IDs present on the key that issued the
signature. Defaults to no. See also --photo-viewer.

show-policy-urls
Show policy URLs in the signature being verified. De-
faults to yes.

show-notations
show-std-notations
show-user-notations
Show all, IETF standard, or user-defined signature nota-
tions in the signature being verified. Defaults to IETF
standard.

show-keyserver-urls
Show any preferred keyserver URL in the signature being
verified. Defaults to yes.

show-uid-validity
Display the calculated validity of the user IDs on the
key that issued the signature. Defaults to yes.

show-unusable-uids
Show revoked and expired user IDs during signature veri-
fication. Defaults to no.

show-primary-uid-only
Show only the primary user ID during signature verifica-
tion. That is all the AKA lines as well as photo Ids are
not shown with the signature verification status.

pka-lookups
Enable PKA lookups to verify sender addresses. Note that
PKA is based on DNS, and so enabling this option may dis-
close information on when and what signatures are veri-
fied or to whom data is encrypted. This is similar to the
"web bug" described for the --auto-key-retrieve option.

pka-trust-increase
Raise the trust in a signature to full if the signature
passes PKA validation. This option is only meaningful if
pka-lookups is set.

--enable-large-rsa
--disable-large-rsa
With --generate-key and --batch, enable the creation of RSA se-
cret keys as large as 8192 bit. Note: 8192 bit is more than is
generally recommended. These large keys don't significantly im-
prove security, but they are more expensive to use, and their
signatures and certifications are larger. This option is only
available if the binary was build with large-secmem support.

--enable-dsa2
--disable-dsa2
Enable hash truncation for all DSA keys even for old DSA Keys up
to 1024 bit. This is also the default with --openpgp. Note
that older versions of GnuPG also required this flag to allow
the generation of DSA larger than 1024 bit.

--photo-viewer string
This is the command line that should be run to view a photo ID.
"%i" will be expanded to a filename containing the photo. "%I"
does the same, except the file will not be deleted once the
viewer exits. Other flags are "%k" for the key ID, "%K" for the
long key ID, "%f" for the key fingerprint, "%t" for the exten-
sion of the image type (e.g. "jpg"), "%T" for the MIME type of
the image (e.g. "image/jpeg"), "%v" for the single-character
calculated validity of the image being viewed (e.g. "f"), "%V"
for the calculated validity as a string (e.g. "full"), "%U" for
a base32 encoded hash of the user ID, and "%%" for an actual
percent sign. If neither %i or %I are present, then the photo
will be supplied to the viewer on standard input.

On Unix the default viewer is xloadimage -fork -quiet -title
'KeyID 0x%k' STDIN with a fallback to display -title 'KeyID
0x%k' %i and finally to xdg-open %i. On Windows !ShellExecute
400 %i is used; here the command is a meta command to use that
API call followed by a wait time in milliseconds which is used
to give the viewer time to read the temporary image file before
gpg deletes it again. Note that if your image viewer program is
not secure, then executing it from gpg does not make it secure.

--exec-path string
Sets a list of directories to search for photo viewers If not
provided photo viewers use the PATH environment variable.

--keyring file
Add file to the current list of keyrings. If file begins with a
tilde and a slash, these are replaced by the $HOME directory. If
the filename does not contain a slash, it is assumed to be in
the GnuPG home directory ("~/.gnupg" if --homedir or $GNUPGHOME
is not used).

Note that this adds a keyring to the current list. If the intent
is to use the specified keyring alone, use --keyring along with
--no-default-keyring.

If the option --no-keyring has been used no keyrings will be
used at all.

--secret-keyring file
This is an obsolete option and ignored. All secret keys are
stored in the 'private-keys-v1.d' directory below the GnuPG home
directory.

--primary-keyring file
Designate file as the primary public keyring. This means that
newly imported keys (via --import or keyserver --recv-from) will
go to this keyring.

--trustdb-name file
Use file instead of the default trustdb. If file begins with a
tilde and a slash, these are replaced by the $HOME directory. If
the filename does not contain a slash, it is assumed to be in
the GnuPG home directory ('~/.gnupg' if --homedir or $GNUPGHOME
is not used).

--homedir dir
Set the name of the home directory to dir. If this option is not
used, the home directory defaults to '~/.gnupg'. It is only
recognized when given on the command line. It also overrides
any home directory stated through the environment variable
'GNUPGHOME' or (on Windows systems) by means of the Registry en-
try HKCU\Software\GNU\GnuPG:HomeDir.

On Windows systems it is possible to install GnuPG as a portable
application. In this case only this command line option is con-
sidered, all other ways to set a home directory are ignored.

To install GnuPG as a portable application under Windows, create
an empty file named 'gpgconf.ctl' in the same directory as the
tool 'gpgconf.exe'. The root of the installation is then that
directory; or, if 'gpgconf.exe' has been installed directly be-
low a directory named 'bin', its parent directory. You also
need to make sure that the following directories exist and are
writable: 'ROOT/home' for the GnuPG home and
'ROOT/var/cache/gnupg' for internal cache files.

--display-charset name
Set the name of the native character set. This is used to con-
vert some informational strings like user IDs to the proper
UTF-8 encoding. Note that this has nothing to do with the char-
acter set of data to be encrypted or signed; GnuPG does not re-
code user-supplied data. If this option is not used, the default
character set is determined from the current locale. A verbosity
level of 3 shows the chosen set. Valid values for name are:

iso-8859-1
This is the Latin 1 set.

iso-8859-2
The Latin 2 set.

iso-8859-15
This is currently an alias for the Latin 1 set.

koi8-r The usual Russian set (RFC-1489).

utf-8 Bypass all translations and assume that the OS uses na-
tive UTF-8 encoding.

--utf8-strings
--no-utf8-strings
Assume that command line arguments are given as UTF-8 strings.
The default (--no-utf8-strings) is to assume that arguments are
encoded in the character set as specified by --display-charset.
These options affect all following arguments. Both options may
be used multiple times.

--options file
Read options from file and do not try to read them from the de-
fault options file in the homedir (see --homedir). This option
is ignored if used in an options file.

--no-options
Shortcut for --options /dev/null. This option is detected before
an attempt to open an option file. Using this option will also
prevent the creation of a '~/.gnupg' homedir.

-z n
--compress-level n
--bzip2-compress-level n
Set compression level to n for the ZIP and ZLIB compression al-
gorithms. The default is to use the default compression level of
zlib (normally 6). --bzip2-compress-level sets the compression
level for the BZIP2 compression algorithm (defaulting to 6 as
well). This is a different option from --compress-level since
BZIP2 uses a significant amount of memory for each additional
compression level. -z sets both. A value of 0 for n disables
compression.

--bzip2-decompress-lowmem
Use a different decompression method for BZIP2 compressed files.
This alternate method uses a bit more than half the memory, but
also runs at half the speed. This is useful under extreme low
memory circumstances when the file was originally compressed at
a high --bzip2-compress-level.

--mangle-dos-filenames
--no-mangle-dos-filenames
Older version of Windows cannot handle filenames with more than
one dot. --mangle-dos-filenames causes GnuPG to replace (rather
than add to) the extension of an output filename to avoid this
problem. This option is off by default and has no effect on non-
Windows platforms.

--ask-cert-level
--no-ask-cert-level
When making a key signature, prompt for a certification level.
If this option is not specified, the certification level used is
set via --default-cert-level. See --default-cert-level for in-
formation on the specific levels and how they are used. --no-
ask-cert-level disables this option. This option defaults to no.

--default-cert-level n
The default to use for the check level when signing a key.

0 means you make no particular claim as to how carefully you
verified the key.

1 means you believe the key is owned by the person who claims to
own it but you could not, or did not verify the key at all. This
is useful for a "persona" verification, where you sign the key
of a pseudonymous user.

2 means you did casual verification of the key. For example,
this could mean that you verified the key fingerprint and
checked the user ID on the key against a photo ID.

3 means you did extensive verification of the key. For example,
this could mean that you verified the key fingerprint with the
owner of the key in person, and that you checked, by means of a
hard to forge document with a photo ID (such as a passport) that
the name of the key owner matches the name in the user ID on the
key, and finally that you verified (by exchange of email) that
the email address on the key belongs to the key owner.

Note that the examples given above for levels 2 and 3 are just
that: examples. In the end, it is up to you to decide just what
"casual" and "extensive" mean to you.

This option defaults to 0 (no particular claim).

--min-cert-level
When building the trust database, treat any signatures with a
certification level below this as invalid. Defaults to 2, which
disregards level 1 signatures. Note that level 0 "no particular
claim" signatures are always accepted.

--trusted-key long key ID
Assume that the specified key (which must be given as a full 8
byte key ID) is as trustworthy as one of your own secret keys.
This option is useful if you don't want to keep your secret keys
(or one of them) online but still want to be able to check the
validity of a given recipient's or signator's key.

--trust-model {pgp|classic|tofu|tofu+pgp|direct|always|auto}
Set what trust model GnuPG should follow. The models are:

pgp This is the Web of Trust combined with trust signatures
as used in PGP 5.x and later. This is the default trust
model when creating a new trust database.

classic
This is the standard Web of Trust as introduced by PGP 2.

tofu

TOFU stands for Trust On First Use. In this trust model,
the first time a key is seen, it is memorized. If later
another key with a user id with the same email address is
seen, both keys are marked as suspect. In that case, the
next time either is used, a warning is displayed describ-
ing the conflict, why it might have occurred (either the
user generated a new key and failed to cross sign the old
and new keys, the key is forgery, or a man-in-the-middle
attack is being attempted), and the user is prompted to
manually confirm the validity of the key in question.

Because a potential attacker is able to control the email
address and thereby circumvent the conflict detection al-
gorithm by using an email address that is similar in ap-
pearance to a trusted email address, whenever a message
is verified, statistics about the number of messages
signed with the key are shown. In this way, a user can
easily identify attacks using fake keys for regular cor-
respondents.

When compared with the Web of Trust, TOFU offers signifi-
cantly weaker security guarantees. In particular, TOFU
only helps ensure consistency (that is, that the binding
between a key and email address doesn't change). A major
advantage of TOFU is that it requires little maintenance
to use correctly. To use the web of trust properly, you
need to actively sign keys and mark users as trusted in-
troducers. This is a time-consuming process and anecdo-
tal evidence suggests that even security-conscious users
rarely take the time to do this thoroughly and instead
rely on an ad-hoc TOFU process.

In the TOFU model, policies are associated with bindings
between keys and email addresses (which are extracted
from user ids and normalized). There are five policies,
which can be set manually using the --tofu-policy option.
The default policy can be set using the --tofu-default-
policy option.

The TOFU policies are: auto, good, unknown, bad and ask.
The auto policy is used by default (unless overridden by
--tofu-default-policy) and marks a binding as marginally
trusted. The good, unknown and bad policies mark a bind-
ing as fully trusted, as having unknown trust or as hav-
ing trust never, respectively. The unknown policy is
useful for just using TOFU to detect conflicts, but to
never assign positive trust to a binding. The final pol-
icy, ask prompts the user to indicate the binding's
trust. If batch mode is enabled (or input is inappropri-
ate in the context), then the user is not prompted and
the undefined trust level is returned.

tofu+pgp
This trust model combines TOFU with the Web of Trust.
This is done by computing the trust level for each model
and then taking the maximum trust level where the trust
levels are ordered as follows: unknown < undefined < mar-
ginal < fully < ultimate < expired < never.

By setting --tofu-default-policy=unknown, this model can
be used to implement the web of trust with TOFU's con-
flict detection algorithm, but without its assignment of
positive trust values, which some security-conscious
users don't like.

direct Key validity is set directly by the user and not calcu-
lated via the Web of Trust. This model is solely based
on the key and does not distinguish user IDs. Note that
when changing to another trust model the trust values as-
signed to a key are transformed into ownertrust values,
which also indicate how you trust the owner of the key to
sign other keys.

always Skip key validation and assume that used keys are always
fully valid. You generally won't use this unless you are
using some external validation scheme. This option also
suppresses the "[uncertain]" tag printed with signature
checks when there is no evidence that the user ID is
bound to the key. Note that this trust model still does
not allow the use of expired, revoked, or disabled keys.

auto Select the trust model depending on whatever the internal
trust database says. This is the default model if such a
database already exists. Note that a tofu trust model is
not considered here and must be enabled explicitly.

--auto-key-locate mechanisms
--no-auto-key-locate
GnuPG can automatically locate and retrieve keys as needed using
this option. This happens when encrypting to an email address
(in the "user@example.com" form), and there are no "user@exam-
ple.com" keys on the local keyring. This option takes any num-
ber of the mechanisms listed below, in the order they are to be
tried. Instead of listing the mechanisms as comma delimited ar-
guments, the option may also be given several times to add more
mechanism. The option --no-auto-key-locate or the mechanism
"clear" resets the list. The default is "local,wkd".

cert Locate a key using DNS CERT, as specified in RFC-4398.

pka Locate a key using DNS PKA.

dane Locate a key using DANE, as specified in draft-ietf-dane-
openpgpkey-05.txt.

wkd Locate a key using the Web Key Directory protocol.

ldap Using DNS Service Discovery, check the domain in question
for any LDAP keyservers to use. If this fails, attempt
to locate the key using the PGP Universal method of
checking 'ldap://keys.(thedomain)'.

keyserver
Locate a key using a keyserver.

keyserver-URL
In addition, a keyserver URL as used in the dirmngr con-
figuration may be used here to query that particular key-
server.

local Locate the key using the local keyrings. This mechanism
allows the user to select the order a local key lookup is
done. Thus using '--auto-key-locate local' is identical
to --no-auto-key-locate.

nodefault
This flag disables the standard local key lookup, done
before any of the mechanisms defined by the --auto-key-
locate are tried. The position of this mechanism in the
list does not matter. It is not required if local is
also used.

clear Clear all defined mechanisms. This is useful to override
mechanisms given in a config file. Note that a nodefault
in mechanisms will also be cleared unless it is given af-
ter the clear.

--auto-key-retrieve
--no-auto-key-retrieve
These options enable or disable the automatic retrieving of keys
from a keyserver when verifying signatures made by keys that are
not on the local keyring. The default is --no-auto-key-re-
trieve.

The order of methods tried to lookup the key is:

1. If a preferred keyserver is specified in the signature and
the option honor-keyserver-url is active (which is not the de-
fault), that keyserver is tried. Note that the creator of the
signature uses the option --sig-keyserver-url to specify the
preferred keyserver for data signatures.

2. If the signature has the Signer's UID set (e.g. using
--sender while creating the signature) a Web Key Directory (WKD)
lookup is done. This is the default configuration but can be
disabled by removing WKD from the auto-key-locate list or by us-
ing the option --disable-signer-uid.

3. If the option honor-pka-record is active, the legacy PKA
method is used.

4. If any keyserver is configured and the Issuer Fingerprint is
part of the signature (since GnuPG 2.1.16), the configured key-
servers are tried.

Note that this option makes a "web bug" like behavior possible.
Keyserver or Web Key Directory operators can see which keys you
request, so by sending you a message signed by a brand new key
(which you naturally will not have on your local keyring), the
operator can tell both your IP address and the time when you
verified the signature.

--keyid-format {none|short|0xshort|long|0xlong}
Select how to display key IDs. "none" does not show the key ID
at all but shows the fingerprint in a separate line. "short" is
the traditional 8-character key ID. "long" is the more accurate
(but less convenient) 16-character key ID. Add an "0x" to ei-
ther to include an "0x" at the beginning of the key ID, as in
0x99242560. Note that this option is ignored if the option
--with-colons is used.

--keyserver name
This option is deprecated - please use the --keyserver in 'dirm-
ngr.conf' instead.

Use name as your keyserver. This is the server that --receive-
keys, --send-keys, and --search-keys will communicate with to
receive keys from, send keys to, and search for keys on. The
format of the name is a URI: `scheme:[//]keyservername[:port]'
The scheme is the type of keyserver: "hkp" for the HTTP (or com-
patible) keyservers, "ldap" for the LDAP keyservers, or "mailto"
for the Graff email keyserver. Note that your particular instal-
lation of GnuPG may have other keyserver types available as
well. Keyserver schemes are case-insensitive. After the key-
server name, optional keyserver configuration options may be
provided. These are the same as the global --keyserver-options
from below, but apply only to this particular keyserver.

Most keyservers synchronize with each other, so there is gener-
ally no need to send keys to more than one server. The keyserver
hkp://keys.gnupg.net uses round robin DNS to give a different
keyserver each time you use it.

--keyserver-options {name=value}
This is a space or comma delimited string that gives options for
the keyserver. Options can be prefixed with a `no-' to give the
opposite meaning. Valid import-options or export-options may be
used here as well to apply to importing (--recv-key) or export-
ing (--send-key) a key from a keyserver. While not all options
are available for all keyserver types, some common options are:

include-revoked
When searching for a key with --search-keys, include keys
that are marked on the keyserver as revoked. Note that
not all keyservers differentiate between revoked and un-
revoked keys, and for such keyservers this option is
meaningless. Note also that most keyservers do not have
cryptographic verification of key revocations, and so
turning this option off may result in skipping keys that
are incorrectly marked as revoked.

include-disabled
When searching for a key with --search-keys, include keys
that are marked on the keyserver as disabled. Note that
this option is not used with HKP keyservers.

auto-key-retrieve
This is an obsolete alias for the option auto-key-re-
trieve. Please do not use it; it will be removed in fu-
ture versions..

honor-keyserver-url
When using --refresh-keys, if the key in question has a
preferred keyserver URL, then use that preferred key-
server to refresh the key from. In addition, if auto-key-
retrieve is set, and the signature being verified has a
preferred keyserver URL, then use that preferred key-
server to fetch the key from. Note that this option in-
troduces a "web bug": The creator of the key can see when
the keys is refreshed. Thus this option is not enabled
by default.

honor-pka-record
If --auto-key-retrieve is used, and the signature being
verified has a PKA record, then use the PKA information
to fetch the key. Defaults to "yes".

include-subkeys
When receiving a key, include subkeys as potential tar-
gets. Note that this option is not used with HKP key-
servers, as they do not support retrieving keys by subkey
id.

timeout
http-proxy=value
verbose
debug
check-cert

ca-cert-file
These options have no more function since GnuPG 2.1. Use
the dirmngr configuration options instead.

The default list of options is: "self-sigs-only, repair-keys, repair-
pks-subkey-bug, export-attributes, honor-pka-record".

--completes-needed n
Number of completely trusted users to introduce a new key signer
(defaults to 1).

--marginals-needed n
Number of marginally trusted users to introduce a new key signer
(defaults to 3)

--tofu-default-policy {auto|good|unknown|bad|ask}
The default TOFU policy (defaults to auto). For more informa-
tion about the meaning of this option, see: [trust-model-tofu].

--max-cert-depth n
Maximum depth of a certification chain (default is 5).

--no-sig-cache
Do not cache the verification status of key signatures. Caching
gives a much better performance in key listings. However, if you
suspect that your public keyring is not safe against write modi-
fications, you can use this option to disable the caching. It
probably does not make sense to disable it because all kind of
damage can be done if someone else has write access to your pub-
lic keyring.

--auto-check-trustdb
--no-auto-check-trustdb
If GnuPG feels that its information about the Web of Trust has
to be updated, it automatically runs the --check-trustdb command
internally. This may be a time consuming process. --no-auto-
check-trustdb disables this option.

--use-agent
--no-use-agent
This is dummy option. gpg always requires the agent.

--gpg-agent-info
This is dummy option. It has no effect when used with gpg.

--agent-program file
Specify an agent program to be used for secret key operations.
The default value is determined by running gpgconf with the op-
tion --list-dirs. Note that the pipe symbol (|) is used for a
regression test suite hack and may thus not be used in the file
name.

--dirmngr-program file
Specify a dirmngr program to be used for keyserver access. The
default value is '/usr/bin/dirmngr'.

--disable-dirmngr
Entirely disable the use of the Dirmngr.

--no-autostart
Do not start the gpg-agent or the dirmngr if it has not yet been
started and its service is required. This option is mostly use-
ful on machines where the connection to gpg-agent has been redi-
rected to another machines. If dirmngr is required on the re-
mote machine, it may be started manually using gpgconf --launch
dirmngr.

--lock-once
Lock the databases the first time a lock is requested and do not
release the lock until the process terminates.

--lock-multiple
Release the locks every time a lock is no longer needed. Use
this to override a previous --lock-once from a config file.

--lock-never
Disable locking entirely. This option should be used only in
very special environments, where it can be assured that only one
process is accessing those files. A bootable floppy with a
stand-alone encryption system will probably use this. Improper
usage of this option may lead to data and key corruption.

--exit-on-status-write-error
This option will cause write errors on the status FD to immedi-
ately terminate the process. That should in fact be the default
but it never worked this way and thus we need an option to en-
able this, so that the change won't break applications which
close their end of a status fd connected pipe too early. Using
this option along with --enable-progress-filter may be used to
cleanly cancel long running gpg operations.

--limit-card-insert-tries n
With n greater than 0 the number of prompts asking to insert a
smartcard gets limited to N-1. Thus with a value of 1 gpg won't
at all ask to insert a card if none has been inserted at
startup. This option is useful in the configuration file in case
an application does not know about the smartcard support and
waits ad infinitum for an inserted card.

--no-random-seed-file
GnuPG uses a file to store its internal random pool over invoca-
tions. This makes random generation faster; however sometimes
write operations are not desired. This option can be used to
achieve that with the cost of slower random generation.

--no-greeting
Suppress the initial copyright message.

--no-secmem-warning
Suppress the warning about "using insecure memory".

--no-permission-warning
Suppress the warning about unsafe file and home directory
(--homedir) permissions. Note that the permission checks that
GnuPG performs are not intended to be authoritative, but rather
they simply warn about certain common permission problems. Do
not assume that the lack of a warning means that your system is
secure.

Note that the warning for unsafe --homedir permissions cannot be
suppressed in the gpg.conf file, as this would allow an attacker
to place an unsafe gpg.conf file in place, and use this file to
suppress warnings about itself. The --homedir permissions warn-
ing may only be suppressed on the command line.

--require-secmem
--no-require-secmem
Refuse to run if GnuPG cannot get secure memory. Defaults to no
(i.e. run, but give a warning).

--require-cross-certification
--no-require-cross-certification
When verifying a signature made from a subkey, ensure that the
cross certification "back signature" on the subkey is present
and valid. This protects against a subtle attack against sub-
keys that can sign. Defaults to --require-cross-certification
for gpg.

--expert
--no-expert
Allow the user to do certain nonsensical or "silly" things like
signing an expired or revoked key, or certain potentially incom-
patible things like generating unusual key types. This also dis-
ables certain warning messages about potentially incompatible
actions. As the name implies, this option is for experts only.
If you don't fully understand the implications of what it allows
you to do, leave this off. --no-expert disables this option.

Key related options

--recipient name
-r Encrypt for user id name. If this option or --hidden-recipient
is not specified, GnuPG asks for the user-id unless --default-
recipient is given.

--hidden-recipient name
-R Encrypt for user ID name, but hide the key ID of this user's
key. This option helps to hide the receiver of the message and
is a limited countermeasure against traffic analysis. If this
option or --recipient is not specified, GnuPG asks for the user
ID unless --default-recipient is given.

--recipient-file file
-f This option is similar to --recipient except that it encrypts to
a key stored in the given file. file must be the name of a file
containing exactly one key. gpg assumes that the key in this
file is fully valid.

--hidden-recipient-file file
-F This option is similar to --hidden-recipient except that it en-
crypts to a key stored in the given file. file must be the name
of a file containing exactly one key. gpg assumes that the key
in this file is fully valid.

--encrypt-to name
Same as --recipient but this one is intended for use in the op-
tions file and may be used with your own user-id as an "encrypt-
to-self". These keys are only used when there are other recipi-
ents given either by use of --recipient or by the asked user id.
No trust checking is performed for these user ids and even dis-
abled keys can be used.

--hidden-encrypt-to name
Same as --hidden-recipient but this one is intended for use in
the options file and may be used with your own user-id as a hid-
den "encrypt-to-self". These keys are only used when there are
other recipients given either by use of --recipient or by the
asked user id. No trust checking is performed for these user
ids and even disabled keys can be used.

--no-encrypt-to
Disable the use of all --encrypt-to and --hidden-encrypt-to
keys.

--group {name=value}
Sets up a named group, which is similar to aliases in email pro-
grams. Any time the group name is a recipient (-r or --recipi-
ent), it will be expanded to the values specified. Multiple
groups with the same name are automatically merged into a single
group.

The values are key IDs or fingerprints, but any key description
is accepted. Note that a value with spaces in it will be treated
as two different values. Note also there is only one level of
expansion --- you cannot make an group that points to another
group. When used from the command line, it may be necessary to
quote the argument to this option to prevent the shell from
treating it as multiple arguments.

--ungroup name
Remove a given entry from the --group list.

--no-groups
Remove all entries from the --group list.

--local-user name
-u Use name as the key to sign with. Note that this option over-
rides --default-key.

--sender mbox
This option has two purposes. mbox must either be a complete
user id with a proper mail address or just a mail address. When
creating a signature this option tells gpg the user id of a key
used to make a signature if the key was not directly specified
by a user id. When verifying a signature the mbox is used to
restrict the information printed by the TOFU code to matching
user ids.

--try-secret-key name
For hidden recipients GPG needs to know the keys to use for
trial decryption. The key set with --default-key is always
tried first, but this is often not sufficient. This option al-
lows setting more keys to be used for trial decryption. Al-
though any valid user-id specification may be used for name it
makes sense to use at least the long keyid to avoid ambiguities.
Note that gpg-agent might pop up a pinentry for a lot keys to do
the trial decryption. If you want to stop all further trial de-
cryption you may use close-window button instead of the cancel
button.

--try-all-secrets
Don't look at the key ID as stored in the message but try all
secret keys in turn to find the right decryption key. This op-
tion forces the behaviour as used by anonymous recipients (cre-
ated by using --throw-keyids or --hidden-recipient) and might
come handy in case where an encrypted message contains a bogus
key ID.

--skip-hidden-recipients
--no-skip-hidden-recipients
During decryption skip all anonymous recipients. This option
helps in the case that people use the hidden recipients feature
to hide their own encrypt-to key from others. If one has many
secret keys this may lead to a major annoyance because all keys
are tried in turn to decrypt something which was not really in-
tended for it. The drawback of this option is that it is cur-
rently not possible to decrypt a message which includes real
anonymous recipients.

Input and Output

--armor
-a Create ASCII armored output. The default is to create the bi-
nary OpenPGP format.

--no-armor
Assume the input data is not in ASCII armored format.

--output file
-o file
Write output to file. To write to stdout use - as the filename.

--max-output n
This option sets a limit on the number of bytes that will be
generated when processing a file. Since OpenPGP supports various
levels of compression, it is possible that the plaintext of a
given message may be significantly larger than the original
OpenPGP message. While GnuPG works properly with such messages,
there is often a desire to set a maximum file size that will be
generated before processing is forced to stop by the OS limits.
Defaults to 0, which means "no limit".

--input-size-hint n
This option can be used to tell GPG the size of the input data
in bytes. n must be a positive base-10 number. This option is
only useful if the input is not taken from a file. GPG may use
this hint to optimize its buffer allocation strategy. It is
also used by the --status-fd line ``PROGRESS'' to provide a
value for ``total'' if that is not available by other means.

--key-origin string[,url]
gpg can track the origin of a key. Certain origins are implic-
itly known (e.g. keyserver, web key directory) and set. For a
standard import the origin of the keys imported can be set with
this option. To list the possible values use "help" for string.
Some origins can store an optional url argument. That URL can
appended to string after a comma.

--import-options parameters
This is a space or comma delimited string that gives options for
importing keys. Options can be prepended with a `no-' to give
the opposite meaning. The options are:

import-local-sigs
Allow importing key signatures marked as "local". This is
not generally useful unless a shared keyring scheme is
being used. Defaults to no.

keep-ownertrust
Normally possible still existing ownertrust values of a
key are cleared if a key is imported. This is in general
desirable so that a formerly deleted key does not auto-
matically gain an ownertrust values merely due to import.
On the other hand it is sometimes necessary to re-import
a trusted set of keys again but keeping already assigned
ownertrust values. This can be achieved by using this
option.

repair-pks-subkey-bug
During import, attempt to repair the damage caused by the
PKS keyserver bug (pre version 0.9.6) that mangles keys
with multiple subkeys. Note that this cannot completely
repair the damaged key as some crucial data is removed by
the keyserver, but it does at least give you back one
subkey. Defaults to no for regular --import and to yes
for keyserver --receive-keys.

import-show
show-only
Show a listing of the key as imported right before it is
stored. This can be combined with the option --dry-run
to only look at keys; the option show-only is a shortcut
for this combination. The command --show-keys is another
shortcut for this. Note that suffixes like '#' for "sec"
and "sbb" lines may or may not be printed.

import-export
Run the entire import code but instead of storing the key
to the local keyring write it to the output. The export
options export-pka and export-dane affect the output.
This option can be used to remove all invalid parts from
a key without the need to store it.

merge-only
During import, allow key updates to existing keys, but do
not allow any new keys to be imported. Defaults to no.

import-clean
After import, compact (remove all signatures except the
self-signature) any user IDs from the new key that are
not usable. Then, remove any signatures from the new key
that are not usable. This includes signatures that were
issued by keys that are not present on the keyring. This
option is the same as running the --edit-key command
"clean" after import. Defaults to no.

self-sigs-only
Accept only self-signatures while importing a key. All
other key signatures are skipped at an early import
stage. This option can be used with keyserver-options to
mitigate attempts to flood a key with bogus signatures
from a keyserver. The drawback is that all other valid
key signatures, as required by the Web of Trust are also
not imported. Note that when using this option along
with import-clean it suppresses the final clean step af-
ter merging the imported key into the existing key.

repair-keys
After import, fix various problems with the keys. For
example, this reorders signatures, and strips duplicate
signatures. Defaults to yes.

import-minimal
Import the smallest key possible. This removes all signa-
tures except the most recent self-signature on each user
ID. This option is the same as running the --edit-key
command "minimize" after import. Defaults to no.

restore
import-restore
Import in key restore mode. This imports all data which
is usually skipped during import; including all GnuPG
specific data. All other contradicting options are over-
ridden.

--import-filter {name=expr}
--export-filter {name=expr}
These options define an import/export filter which are applied
to the imported/exported keyblock right before it will be
stored/written. name defines the type of filter to use, expr
the expression to evaluate. The option can be used several
times which then appends more expression to the same name.

The available filter types are:

keep-uid
This filter will keep a user id packet and its dependent
packets in the keyblock if the expression evaluates to
true.

drop-subkey
This filter drops the selected subkeys. Currently only
implemented for --export-filter.

drop-sig
This filter drops the selected key signatures on user
ids. Self-signatures are not considered. Currently only
implemented for --import-filter.

For the syntax of the expression see the chapter "FILTER EXPRESSIONS".
The property names for the expressions depend on the actual filter type
and are indicated in the following table.

The available properties are:

uid A string with the user id. (keep-uid)

mbox The addr-spec part of a user id with mailbox or the empty
string. (keep-uid)

key_algo
A number with the public key algorithm of a key or subkey
packet. (drop-subkey)

key_created
key_created_d
The first is the timestamp a public key or subkey packet
was created. The second is the same but given as an ISO
string, e.g. "2016-08-17". (drop-subkey)

primary
Boolean indicating whether the user id is the primary
one. (keep-uid)

expired
Boolean indicating whether a user id (keep-uid), a key
(drop-subkey), or a signature (drop-sig) expired.

revoked
Boolean indicating whether a user id (keep-uid) or a key
(drop-subkey) has been revoked.

disabled
Boolean indicating whether a primary key is disabled.
(not used)

secret Boolean indicating whether a key or subkey is a secret
one. (drop-subkey)

usage A string indicating the usage flags for the subkey, from
the sequence ``ecsa?''. For example, a subkey capable of
just signing and authentication would be an exact match
for ``sa''. (drop-subkey)

sig_created
sig_created_d
The first is the timestamp a signature packet was cre-
ated. The second is the same but given as an ISO date
string, e.g. "2016-08-17". (drop-sig)

sig_algo
A number with the public key algorithm of a signature
packet. (drop-sig)

sig_digest_algo
A number with the digest algorithm of a signature packet.
(drop-sig)

--export-options parameters
This is a space or comma delimited string that gives options for
exporting keys. Options can be prepended with a `no-' to give
the opposite meaning. The options are:

export-local-sigs
Allow exporting key signatures marked as "local". This is
not generally useful unless a shared keyring scheme is
being used. Defaults to no.

export-attributes
Include attribute user IDs (photo IDs) while exporting.
Not including attribute user IDs is useful to export keys
that are going to be used by an OpenPGP program that does
not accept attribute user IDs. Defaults to yes.

export-sensitive-revkeys
Include designated revoker information that was marked as
"sensitive". Defaults to no.

backup
export-backup
Export for use as a backup. The exported data includes
all data which is needed to restore the key or keys later
with GnuPG. The format is basically the OpenPGP format
but enhanced with GnuPG specific data. All other contra-
dicting options are overridden.

export-clean
Compact (remove all signatures from) user IDs on the key
being exported if the user IDs are not usable. Also, do
not export any signatures that are not usable. This in-
cludes signatures that were issued by keys that are not
present on the keyring. This option is the same as run-
ning the --edit-key command "clean" before export except
that the local copy of the key is not modified. Defaults
to no.

export-minimal
Export the smallest key possible. This removes all signa-
tures except the most recent self-signature on each user
ID. This option is the same as running the --edit-key
command "minimize" before export except that the local
copy of the key is not modified. Defaults to no.

export-pka
Instead of outputting the key material output PKA records
suitable to put into DNS zone files. An ORIGIN line is
printed before each record to allow diverting the records
to the corresponding zone file.

export-dane
Instead of outputting the key material output OpenPGP
DANE records suitable to put into DNS zone files. An
ORIGIN line is printed before each record to allow di-
verting the records to the corresponding zone file.

--with-colons
Print key listings delimited by colons. Note that the output
will be encoded in UTF-8 regardless of any --display-charset
setting. This format is useful when GnuPG is called from scripts
and other programs as it is easily machine parsed. The details
of this format are documented in the file 'doc/DETAILS', which
is included in the GnuPG source distribution.

--fixed-list-mode
Do not merge primary user ID and primary key in --with-colon
listing mode and print all timestamps as seconds since
1970-01-01. Since GnuPG 2.0.10, this mode is always used and
thus this option is obsolete; it does not harm to use it though.

--legacy-list-mode
Revert to the pre-2.1 public key list mode. This only affects
the human readable output and not the machine interface (i.e.
--with-colons). Note that the legacy format does not convey
suitable information for elliptic curves.

--with-fingerprint
Same as the command --fingerprint but changes only the format of
the output and may be used together with another command.

--with-subkey-fingerprint
If a fingerprint is printed for the primary key, this option
forces printing of the fingerprint for all subkeys. This could
also be achieved by using the --with-fingerprint twice but by
using this option along with keyid-format "none" a compact fin-
gerprint is printed.

--with-icao-spelling
Print the ICAO spelling of the fingerprint in addition to the
hex digits.

--with-keygrip
Include the keygrip in the key listings. In --with-colons mode
this is implicitly enable for secret keys.

--with-key-origin
Include the locally held information on the origin and last up-
date of a key in a key listing. In --with-colons mode this is
always printed. This data is currently experimental and shall
not be considered part of the stable API.

--with-wkd-hash
Print a Web Key Directory identifier along with each user ID in
key listings. This is an experimental feature and semantics may
change.

--with-secret
Include info about the presence of a secret key in public key
listings done with --with-colons.

OpenPGP protocol specific options

-t, --textmode
--no-textmode
Treat input files as text and store them in the OpenPGP canoni-
cal text form with standard "CRLF" line endings. This also sets
the necessary flags to inform the recipient that the encrypted
or signed data is text and may need its line endings converted
back to whatever the local system uses. This option is useful
when communicating between two platforms that have different
line ending conventions (UNIX-like to Mac, Mac to Windows, etc).
--no-textmode disables this option, and is the default.

--force-v3-sigs
--no-force-v3-sigs

--force-v4-certs
--no-force-v4-certs
These options are obsolete and have no effect since GnuPG 2.1.

--force-mdc
--disable-mdc
These options are obsolete and have no effect since GnuPG 2.2.8.
The MDC is always used. But note: If the creation of a legacy
non-MDC message is exceptionally required, the option --rfc2440
allows for this.

--disable-signer-uid
By default the user ID of the signing key is embedded in the
data signature. As of now this is only done if the signing key
has been specified with local-user using a mail address, or with
sender. This information can be helpful for verifier to locate
the key; see option --auto-key-retrieve.

--personal-cipher-preferences string
Set the list of personal cipher preferences to string. Use gpg
--version to get a list of available algorithms, and use none to
set no preference at all. This allows the user to safely over-
ride the algorithm chosen by the recipient key preferences, as
GPG will only select an algorithm that is usable by all recipi-
ents. The most highly ranked cipher in this list is also used
for the --symmetric encryption command.

--personal-digest-preferences string
Set the list of personal digest preferences to string. Use gpg
--version to get a list of available algorithms, and use none to
set no preference at all. This allows the user to safely over-
ride the algorithm chosen by the recipient key preferences, as
GPG will only select an algorithm that is usable by all recipi-
ents. The most highly ranked digest algorithm in this list is
also used when signing without encryption (e.g. --clear-sign or
--sign).

--personal-compress-preferences string
Set the list of personal compression preferences to string. Use
gpg --version to get a list of available algorithms, and use
none to set no preference at all. This allows the user to
safely override the algorithm chosen by the recipient key pref-
erences, as GPG will only select an algorithm that is usable by
all recipients. The most highly ranked compression algorithm in
this list is also used when there are no recipient keys to con-
sider (e.g. --symmetric).

--s2k-cipher-algo name
Use name as the cipher algorithm for symmetric encryption with a
passphrase if --personal-cipher-preferences and --cipher-algo
are not given. The default is AES-128.

--s2k-digest-algo name
Use name as the digest algorithm used to mangle the passphrases
for symmetric encryption. The default is SHA-1.

--s2k-mode n
Selects how passphrases for symmetric encryption are mangled. If
n is 0 a plain passphrase (which is in general not recommended)
will be used, a 1 adds a salt (which should not be used) to the
passphrase and a 3 (the default) iterates the whole process a
number of times (see --s2k-count).

--s2k-count n
Specify how many times the passphrases mangling for symmetric
encryption is repeated. This value may range between 1024 and
65011712 inclusive. The default is inquired from gpg-agent.
Note that not all values in the 1024-65011712 range are legal
and if an illegal value is selected, GnuPG will round up to the
nearest legal value. This option is only meaningful if --s2k-
mode is set to the default of 3.

Compliance options

These options control what GnuPG is compliant to. Only one of these op-
tions may be active at a time. Note that the default setting of this is
nearly always the correct one. See the INTEROPERABILITY WITH OTHER
OPENPGP PROGRAMS section below before using one of these options.

--gnupg
Use standard GnuPG behavior. This is essentially OpenPGP behav-
ior (see --openpgp), but with some additional workarounds for
common compatibility problems in different versions of PGP. This
is the default option, so it is not generally needed, but it may
be useful to override a different compliance option in the
gpg.conf file.

--openpgp
Reset all packet, cipher and digest options to strict OpenPGP
behavior. Use this option to reset all previous options like
--s2k-*, --cipher-algo, --digest-algo and --compress-algo to
OpenPGP compliant values. All PGP workarounds are disabled.

--rfc4880
Reset all packet, cipher and digest options to strict RFC-4880
behavior. Note that this is currently the same thing as
--openpgp.

--rfc4880bis
Enable experimental features from proposed updates to RFC-4880.
This option can be used in addition to the other compliance op-
tions. Warning: The behavior may change with any GnuPG release
and created keys or data may not be usable with future GnuPG
versions.

--rfc2440
Reset all packet, cipher and digest options to strict RFC-2440
behavior. Note that by using this option encryption packets are
created in a legacy mode without MDC protection. This is dan-
gerous and should thus only be used for experiments. See also
option --ignore-mdc-error.

--pgp6 Set up all options to be as PGP 6 compliant as possible. This
restricts you to the ciphers IDEA (if the IDEA plugin is in-
stalled), 3DES, and CAST5, the hashes MD5, SHA1 and RIPEMD160,
and the compression algorithms none and ZIP. This also disables
--throw-keyids, and making signatures with signing subkeys as
PGP 6 does not understand signatures made by signing subkeys.

This option implies --escape-from-lines.

--pgp7 Set up all options to be as PGP 7 compliant as possible. This is
identical to --pgp6 except that MDCs are not disabled, and the
list of allowable ciphers is expanded to add AES128, AES192,
AES256, and TWOFISH.

--pgp8 Set up all options to be as PGP 8 compliant as possible. PGP 8
is a lot closer to the OpenPGP standard than previous versions
of PGP, so all this does is disable --throw-keyids and set --es-
cape-from-lines. All algorithms are allowed except for the
SHA224, SHA384, and SHA512 digests.

--compliance string
This option can be used instead of one of the options above.
Valid values for string are the above option names (without the
double dash) and possibly others as shown when using "help" for
value.

Doing things one usually doesn't want to do

-n
--dry-run
Don't make any changes (this is not completely implemented).

--list-only
Changes the behaviour of some commands. This is like --dry-run
but different in some cases. The semantic of this option may be
extended in the future. Currently it only skips the actual de-
cryption pass and therefore enables a fast listing of the en-
cryption keys.

-i
--interactive
Prompt before overwriting any files.

--debug-level level
Select the debug level for investigating problems. level may be
a numeric value or by a keyword:

none No debugging at all. A value of less than 1 may be used
instead of the keyword.

basic Some basic debug messages. A value between 1 and 2 may
be used instead of the keyword.

advanced
More verbose debug messages. A value between 3 and 5 may
be used instead of the keyword.

expert Even more detailed messages. A value between 6 and 8 may
be used instead of the keyword.

guru All of the debug messages you can get. A value greater
than 8 may be used instead of the keyword. The creation
of hash tracing files is only enabled if the keyword is
used.

How these messages are mapped to the actual debugging flags is not
specified and may change with newer releases of this program. They are
however carefully selected to best aid in debugging.

--debug flags
Set debugging flags. All flags are or-ed and flags may be given
in C syntax (e.g. 0x0042) or as a comma separated list of flag
names. To get a list of all supported flags the single word
"help" can be used.

--debug-all
Set all useful debugging flags.

--debug-iolbf
Set stdout into line buffered mode. This option is only honored
when given on the command line.

--faked-system-time epoch
This option is only useful for testing; it sets the system time
back or forth to epoch which is the number of seconds elapsed
since the year 1970. Alternatively epoch may be given as a full
ISO time string (e.g. "20070924T154812").

If you suffix epoch with an exclamation mark (!), the system
time will appear to be frozen at the specified time.

--enable-progress-filter
Enable certain PROGRESS status outputs. This option allows
frontends to display a progress indicator while gpg is process-
ing larger files. There is a slight performance overhead using
it.

--status-fd n
Write special status strings to the file descriptor n. See the
file DETAILS in the documentation for a listing of them.

--status-file file
Same as --status-fd, except the status data is written to file
file.

--logger-fd n
Write log output to file descriptor n and not to STDERR.

--log-file file
--logger-file file
Same as --logger-fd, except the logger data is written to file
file. Use 'socket://' to log to a socket. Note that in this
version of gpg the option has only an effect if --batch is also
used.

--attribute-fd n
Write attribute subpackets to the file descriptor n. This is
most useful for use with --status-fd, since the status messages
are needed to separate out the various subpackets from the
stream delivered to the file descriptor.

--attribute-file file
Same as --attribute-fd, except the attribute data is written to
file file.

--comment string
--no-comments
Use string as a comment string in cleartext signatures and ASCII
armored messages or keys (see --armor). The default behavior is
not to use a comment string. --comment may be repeated multiple
times to get multiple comment strings. --no-comments removes all
comments. It is a good idea to keep the length of a single com-
ment below 60 characters to avoid problems with mail programs
wrapping such lines. Note that comment lines, like all other
header lines, are not protected by the signature.

--emit-version
--no-emit-version
Force inclusion of the version string in ASCII armored output.
If given once only the name of the program and the major number
is emitted, given twice the minor is also emitted, given thrice
the micro is added, and given four times an operating system
identification is also emitted. --no-emit-version (default)
disables the version line.

--sig-notation {name=value}
--cert-notation {name=value}
-N, --set-notation {name=value}
Put the name value pair into the signature as notation data.
name must consist only of printable characters or spaces, and
must contain a '@' character in the form keyname@domain.exam-
ple.com (substituting the appropriate keyname and domain name,
of course). This is to help prevent pollution of the IETF re-
served notation namespace. The --expert flag overrides the '@'
check. value may be any printable string; it will be encoded in
UTF-8, so you should check that your --display-charset is set
correctly. If you prefix name with an exclamation mark (!), the
notation data will be flagged as critical (rfc4880:5.2.3.16).
--sig-notation sets a notation for data signatures. --cert-nota-
tion sets a notation for key signatures (certifications). --set-
notation sets both.

There are special codes that may be used in notation names. "%k"
will be expanded into the key ID of the key being signed, "%K"
into the long key ID of the key being signed, "%f" into the fin-
gerprint of the key being signed, "%s" into the key ID of the
key making the signature, "%S" into the long key ID of the key
making the signature, "%g" into the fingerprint of the key mak-
ing the signature (which might be a subkey), "%p" into the fin-
gerprint of the primary key of the key making the signature,
"%c" into the signature count from the OpenPGP smartcard, and
"%%" results in a single "%". %k, %K, and %f are only meaningful
when making a key signature (certification), and %c is only
meaningful when using the OpenPGP smartcard.

--known-notation name
Adds name to a list of known critical signature notations. The
effect of this is that gpg will not mark a signature with a
critical signature notation of that name as bad. Note that gpg
already knows by default about a few critical signatures nota-
tion names.

--sig-policy-url string
--cert-policy-url string
--set-policy-url string
Use string as a Policy URL for signatures (rfc4880:5.2.3.20).
If you prefix it with an exclamation mark (!), the policy URL
packet will be flagged as critical. --sig-policy-url sets a pol-
icy url for data signatures. --cert-policy-url sets a policy url
for key signatures (certifications). --set-policy-url sets both.

The same %-expandos used for notation data are available here as
well.

--sig-keyserver-url string
Use string as a preferred keyserver URL for data signatures. If
you prefix it with an exclamation mark (!), the keyserver URL
packet will be flagged as critical.

The same %-expandos used for notation data are available here as
well.

--set-filename string
Use string as the filename which is stored inside messages.
This overrides the default, which is to use the actual filename
of the file being encrypted. Using the empty string for string
effectively removes the filename from the output.

--for-your-eyes-only
--no-for-your-eyes-only
Set the `for your eyes only' flag in the message. This causes
GnuPG to refuse to save the file unless the --output option is
given, and PGP to use a "secure viewer" with a claimed Tempest-
resistant font to display the message. This option overrides
--set-filename. --no-for-your-eyes-only disables this option.

--use-embedded-filename
--no-use-embedded-filename
Try to create a file with a name as embedded in the data. This
can be a dangerous option as it enables overwriting files. De-
faults to no. Note that the option --output overrides this op-
tion.

--cipher-algo name
Use name as cipher algorithm. Running the program with the com-
mand --version yields a list of supported algorithms. If this is
not used the cipher algorithm is selected from the preferences
stored with the key. In general, you do not want to use this op-
tion as it allows you to violate the OpenPGP standard. --per-
sonal-cipher-preferences is the safe way to accomplish the same
thing.

--digest-algo name
Use name as the message digest algorithm. Running the program
with the command --version yields a list of supported algo-
rithms. In general, you do not want to use this option as it al-
lows you to violate the OpenPGP standard. --personal-digest-
preferences is the safe way to accomplish the same thing.

--compress-algo name
Use compression algorithm name. "zlib" is RFC-1950 ZLIB compres-
sion. "zip" is RFC-1951 ZIP compression which is used by PGP.
"bzip2" is a more modern compression scheme that can compress
some things better than zip or zlib, but at the cost of more
memory used during compression and decompression. "uncompressed"
or "none" disables compression. If this option is not used, the
default behavior is to examine the recipient key preferences to
see which algorithms the recipient supports. If all else fails,
ZIP is used for maximum compatibility.

ZLIB may give better compression results than ZIP, as the com-
pression window size is not limited to 8k. BZIP2 may give even
better compression results than that, but will use a signifi-
cantly larger amount of memory while compressing and decompress-
ing. This may be significant in low memory situations. Note,
however, that PGP (all versions) only supports ZIP compression.
Using any algorithm other than ZIP or "none" will make the mes-
sage unreadable with PGP. In general, you do not want to use
this option as it allows you to violate the OpenPGP standard.
--personal-compress-preferences is the safe way to accomplish
the same thing.

--cert-digest-algo name
Use name as the message digest algorithm used when signing a
key. Running the program with the command --version yields a
list of supported algorithms. Be aware that if you choose an al-
gorithm that GnuPG supports but other OpenPGP implementations do
not, then some users will not be able to use the key signatures
you make, or quite possibly your entire key.

--disable-cipher-algo name
Never allow the use of name as cipher algorithm. The given name
will not be checked so that a later loaded algorithm will still
get disabled.

--disable-pubkey-algo name
Never allow the use of name as public key algorithm. The given
name will not be checked so that a later loaded algorithm will
still get disabled.

--throw-keyids
--no-throw-keyids
Do not put the recipient key IDs into encrypted messages. This
helps to hide the receivers of the message and is a limited
countermeasure against traffic analysis. ([Using a little social
engineering anyone who is able to decrypt the message can check
whether one of the other recipients is the one he suspects.])
On the receiving side, it may slow down the decryption process
because all available secret keys must be tried. --no-throw-
keyids disables this option. This option is essentially the same
as using --hidden-recipient for all recipients.

--not-dash-escaped
This option changes the behavior of cleartext signatures so that
they can be used for patch files. You should not send such an
armored file via email because all spaces and line endings are
hashed too. You can not use this option for data which has 5
dashes at the beginning of a line, patch files don't have this.
A special armor header line tells GnuPG about this cleartext
signature option.

--escape-from-lines
--no-escape-from-lines
Because some mailers change lines starting with "From " to
">From " it is good to handle such lines in a special way when
creating cleartext signatures to prevent the mail system from
breaking the signature. Note that all other PGP versions do it
this way too. Enabled by default. --no-escape-from-lines dis-
ables this option.

--passphrase-repeat n
Specify how many times gpg will request a new passphrase be re-
peated. This is useful for helping memorize a passphrase. De-
faults to 1 repetition.

--passphrase-fd n
Read the passphrase from file descriptor n. Only the first line
will be read from file descriptor n. If you use 0 for n, the
passphrase will be read from STDIN. This can only be used if
only one passphrase is supplied.

Note that since Version 2.0 this passphrase is only used if the
option --batch has also been given. Since Version 2.1 the
--pinentry-mode also needs to be set to loopback.

--passphrase-file file
Read the passphrase from file file. Only the first line will be
read from file file. This can only be used if only one
passphrase is supplied. Obviously, a passphrase stored in a file
is of questionable security if other users can read this file.
Don't use this option if you can avoid it.

Note that since Version 2.0 this passphrase is only used if the
option --batch has also been given. Since Version 2.1 the
--pinentry-mode also needs to be set to loopback.

--passphrase string
Use string as the passphrase. This can only be used if only one
passphrase is supplied. Obviously, this is of very questionable
security on a multi-user system. Don't use this option if you
can avoid it.

Note that since Version 2.0 this passphrase is only used if the
option --batch has also been given. Since Version 2.1 the
--pinentry-mode also needs to be set to loopback.

--pinentry-mode mode
Set the pinentry mode to mode. Allowed values for mode are:

default
Use the default of the agent, which is ask.

ask Force the use of the Pinentry.

cancel Emulate use of Pinentry's cancel button.

error Return a Pinentry error (``No Pinentry'').

loopback
Redirect Pinentry queries to the caller. Note that in
contrast to Pinentry the user is not prompted again if he
enters a bad password.

--no-symkey-cache
Disable the passphrase cache used for symmetrical en- and de-
cryption. This cache is based on the message specific salt
value (cf. --s2k-mode).

--request-origin origin
Tell gpg to assume that the operation ultimately originated at
origin. Depending on the origin certain restrictions are ap-
plied and the Pinentry may include an extra note on the origin.
Supported values for origin are: local which is the default, re-
mote to indicate a remote origin or browser for an operation re-
quested by a web browser.

--command-fd n
This is a replacement for the deprecated shared-memory IPC mode.
If this option is enabled, user input on questions is not ex-
pected from the TTY but from the given file descriptor. It
should be used together with --status-fd. See the file doc/DE-
TAILS in the source distribution for details on how to use it.

--command-file file
Same as --command-fd, except the commands are read out of file
file

--allow-non-selfsigned-uid
--no-allow-non-selfsigned-uid
Allow the import and use of keys with user IDs which are not
self-signed. This is not recommended, as a non self-signed user
ID is trivial to forge. --no-allow-non-selfsigned-uid disables.

--allow-freeform-uid
Disable all checks on the form of the user ID while generating a
new one. This option should only be used in very special envi-
ronments as it does not ensure the de-facto standard format of
user IDs.

--ignore-time-conflict
GnuPG normally checks that the timestamps associated with keys
and signatures have plausible values. However, sometimes a sig-
nature seems to be older than the key due to clock problems.
This option makes these checks just a warning. See also --ig-
nore-valid-from for timestamp issues on subkeys.

--ignore-valid-from
GnuPG normally does not select and use subkeys created in the
future. This option allows the use of such keys and thus ex-
hibits the pre-1.0.7 behaviour. You should not use this option
unless there is some clock problem. See also --ignore-time-con-
flict for timestamp issues with signatures.

--ignore-crc-error
The ASCII armor used by OpenPGP is protected by a CRC checksum
against transmission errors. Occasionally the CRC gets mangled
somewhere on the transmission channel but the actual content
(which is protected by the OpenPGP protocol anyway) is still
okay. This option allows GnuPG to ignore CRC errors.

--ignore-mdc-error
This option changes a MDC integrity protection failure into a
warning. It is required to decrypt old messages which did not
use an MDC. It may also be useful if a message is partially
garbled, but it is necessary to get as much data as possible out
of that garbled message. Be aware that a missing or failed MDC
can be an indication of an attack. Use with great caution; see
also option --rfc2440.

--allow-weak-digest-algos
Signatures made with known-weak digest algorithms are normally
rejected with an ``invalid digest algorithm'' message. This op-
tion allows the verification of signatures made with such weak
algorithms. MD5 is the only digest algorithm considered weak by
default. See also --weak-digest to reject other digest algo-
rithms.

--weak-digest name
Treat the specified digest algorithm as weak. Signatures made
over weak digests algorithms are normally rejected. This option
can be supplied multiple times if multiple algorithms should be
considered weak. See also --allow-weak-digest-algos to disable
rejection of weak digests. MD5 is always considered weak, and
does not need to be listed explicitly.

--allow-weak-key-signatures
To avoid a minor risk of collision attacks on third-party key
signatures made using SHA-1, those key signatures are considered
invalid. This options allows to override this restriction.

--no-default-keyring
Do not add the default keyrings to the list of keyrings. Note
that GnuPG will not operate without any keyrings, so if you use
this option and do not provide alternate keyrings via --keyring
or --secret-keyring, then GnuPG will still use the default pub-
lic or secret keyrings.

--no-keyring
Do not use any keyring at all. This overrides the default and
all options which specify keyrings.

--skip-verify
Skip the signature verification step. This may be used to make
the decryption faster if the signature verification is not
needed.

--with-key-data
Print key listings delimited by colons (like --with-colons) and
print the public key data.

--list-signatures
--list-sigs
Same as --list-keys, but the signatures are listed too. This
command has the same effect as using --list-keys with --with-
sig-list. Note that in contrast to --check-signatures the key
signatures are not verified. This command can be used to create
a list of signing keys missing in the local keyring; for exam-
ple:

gpg --list-sigs --with-colons USERID | \
awk -F: '$1=="sig" && $2=="?" {if($13){print $13}else{print $5}}'

--fast-list-mode
Changes the output of the list commands to work faster; this is
achieved by leaving some parts empty. Some applications don't
need the user ID and the trust information given in the list-
ings. By using this options they can get a faster listing. The
exact behaviour of this option may change in future versions.
If you are missing some information, don't use this option.

--no-literal
This is not for normal use. Use the source to see for what it
might be useful.

--set-filesize
This is not for normal use. Use the source to see for what it
might be useful.

--show-session-key
Display the session key used for one message. See --override-
session-key for the counterpart of this option.

We think that Key Escrow is a Bad Thing; however the user should
have the freedom to decide whether to go to prison or to reveal
the content of one specific message without compromising all
messages ever encrypted for one secret key.

You can also use this option if you receive an encrypted message
which is abusive or offensive, to prove to the administrators of
the messaging system that the ciphertext transmitted corresponds
to an inappropriate plaintext so they can take action against
the offending user.

--override-session-key string
--override-session-key-fd fd
Don't use the public key but the session key string respective
the session key taken from the first line read from file de-
scriptor fd. The format of this string is the same as the one
printed by --show-session-key. This option is normally not used
but comes handy in case someone forces you to reveal the content
of an encrypted message; using this option you can do this with-
out handing out the secret key. Note that using --override-ses-
sion-key may reveal the session key to all local users via the
global process table. Often it is useful to combine this option
with --no-keyring.

--ask-sig-expire
--no-ask-sig-expire
When making a data signature, prompt for an expiration time. If
this option is not specified, the expiration time set via --de-
fault-sig-expire is used. --no-ask-sig-expire disables this op-
tion.

--default-sig-expire
The default expiration time to use for signature expiration.
Valid values are "0" for no expiration, a number followed by the
letter d (for days), w (for weeks), m (for months), or y (for
years) (for example "2m" for two months, or "5y" for five
years), or an absolute date in the form YYYY-MM-DD. Defaults to
"0".

--ask-cert-expire
--no-ask-cert-expire
When making a key signature, prompt for an expiration time. If
this option is not specified, the expiration time set via --de-
fault-cert-expire is used. --no-ask-cert-expire disables this
option.

--default-cert-expire
The default expiration time to use for key signature expiration.
Valid values are "0" for no expiration, a number followed by the
letter d (for days), w (for weeks), m (for months), or y (for
years) (for example "2m" for two months, or "5y" for five
years), or an absolute date in the form YYYY-MM-DD. Defaults to
"0".

--default-new-key-algo string
This option can be used to change the default algorithms for key
generation. The string is similar to the arguments required for
the command --quick-add-key but slightly different. For example
the current default of "rsa2048/cert,sign+rsa2048/encr" (or
"rsa3072") can be changed to the value of what we currently call
future default, which is "ed25519/cert,sign+cv25519/encr". You
need to consult the source code to learn the details. Note that
the advanced key generation commands can always be used to spec-
ify a key algorithm directly.

--allow-secret-key-import
This is an obsolete option and is not used anywhere.

--allow-multiple-messages

--no-allow-multiple-messages
Allow processing of multiple OpenPGP messages contained in a
single file or stream. Some programs that call GPG are not pre-
pared to deal with multiple messages being processed together,
so this option defaults to no. Note that versions of GPG prior
to 1.4.7 always allowed multiple messages.

Warning: Do not use this option unless you need it as a tempo-
rary workaround!

--enable-special-filenames
This option enables a mode in which filenames of the form '-&n',
where n is a non-negative decimal number, refer to the file de-
scriptor n and not to a file with that name.

--no-expensive-trust-checks
Experimental use only.

--preserve-permissions
Don't change the permissions of a secret keyring back to user
read/write only. Use this option only if you really know what
you are doing.

--default-preference-list string
Set the list of default preferences to string. This preference
list is used for new keys and becomes the default for "setpref"
in the edit menu.

--default-keyserver-url name
Set the default keyserver URL to name. This keyserver will be
used as the keyserver URL when writing a new self-signature on a
key, which includes key generation and changing preferences.

--list-config
Display various internal configuration parameters of GnuPG. This
option is intended for external programs that call GnuPG to per-
form tasks, and is thus not generally useful. See the file
'doc/DETAILS' in the source distribution for the details of
which configuration items may be listed. --list-config is only
usable with --with-colons set.

--list-gcrypt-config
Display various internal configuration parameters of Libgcrypt.

--gpgconf-list
This command is similar to --list-config but in general only in-
ternally used by the gpgconf tool.

--gpgconf-test
This is more or less dummy action. However it parses the con-
figuration file and returns with failure if the configuration
file would prevent gpg from startup. Thus it may be used to run
a syntax check on the configuration file.

Deprecated options

--show-photos
--no-show-photos
Causes --list-keys, --list-signatures, --list-public-keys,
--list-secret-keys, and verifying a signature to also display
the photo ID attached to the key, if any. See also --photo-
viewer. These options are deprecated. Use --list-options
[no-]show-photos and/or --verify-options [no-]show-photos in-
stead.

--show-keyring
Display the keyring name at the head of key listings to show
which keyring a given key resides on. This option is deprecated:
use --list-options [no-]show-keyring instead.

--always-trust
Identical to --trust-model always. This option is deprecated.

--show-notation
--no-show-notation
Show signature notations in the --list-signatures or --check-
signatures listings as well as when verifying a signature with a
notation in it. These options are deprecated. Use --list-options
[no-]show-notation and/or --verify-options [no-]show-notation
instead.

--show-policy-url
--no-show-policy-url
Show policy URLs in the --list-signatures or --check-signatures
listings as well as when verifying a signature with a policy URL
in it. These options are deprecated. Use --list-options
[no-]show-policy-url and/or --verify-options [no-]show-policy-
url instead.

EXAMPLES
gpg -se -r Bob file
sign and encrypt for user Bob

gpg --clear-sign file
make a cleartext signature

gpg -sb file
make a detached signature

gpg -u 0x12345678 -sb file
make a detached signature with the key 0x12345678

gpg --list-keys user_ID
show keys

gpg --fingerprint user_ID
show fingerprint

gpg --verify pgpfile
gpg --verify sigfile [datafile]
Verify the signature of the file but do not output the data un-
less requested. The second form is used for detached signa-
tures, where sigfile is the detached signature (either ASCII ar-
mored or binary) and datafile are the signed data; if this is
not given, the name of the file holding the signed data is con-
structed by cutting off the extension (".asc" or ".sig") of sig-
file or by asking the user for the filename. If the option
--output is also used the signed data is written to the file
specified by that option; use - to write the signed data to std-
out.

HOW TO SPECIFY A USER ID
There are different ways to specify a user ID to GnuPG. Some of them
are only valid for gpg others are only good for gpgsm. Here is the en-
tire list of ways to specify a key:

By key Id.
This format is deduced from the length of the string and its
content or 0x prefix. The key Id of an X.509 certificate are the
low 64 bits of its SHA-1 fingerprint. The use of key Ids is
just a shortcut, for all automated processing the fingerprint
should be used.

When using gpg an exclamation mark (!) may be appended to force
using the specified primary or secondary key and not to try and
calculate which primary or secondary key to use.

The last four lines of the example give the key ID in their long
form as internally used by the OpenPGP protocol. You can see the
long key ID using the option --with-colons.

234567C4
0F34E556E
01347A56A
0xAB123456

234AABBCC34567C4
0F323456784E56EAB
01AB3FED1347A5612
0x234AABBCC34567C4

By fingerprint.
This format is deduced from the length of the string and its
content or the 0x prefix. Note, that only the 20 byte version
fingerprint is available with gpgsm (i.e. the SHA-1 hash of the
certificate).

When using gpg an exclamation mark (!) may be appended to force
using the specified primary or secondary key and not to try and
calculate which primary or secondary key to use.

The best way to specify a key Id is by using the fingerprint.
This avoids any ambiguities in case that there are duplicated
key IDs.

1234343434343434C434343434343434
123434343434343C3434343434343734349A3434
0E12343434343434343434EAB3484343434343434
0xE12343434343434343434EAB3484343434343434

gpgsm also accepts colons between each pair of hexadecimal digits be-
cause this is the de-facto standard on how to present X.509 finger-
prints. gpg also allows the use of the space separated SHA-1 finger-
print as printed by the key listing commands.

By exact match on OpenPGP user ID.
This is denoted by a leading equal sign. It does not make sense
for X.509 certificates.

=Heinrich Heine <heinrichh@uni-duesseldorf.de>

By exact match on an email address.
This is indicated by enclosing the email address in the usual
way with left and right angles.

<heinrichh@uni-duesseldorf.de>

By partial match on an email address.
This is indicated by prefixing the search string with an @.
This uses a substring search but considers only the mail address
(i.e. inside the angle brackets).

@heinrichh

By exact match on the subject's DN.
This is indicated by a leading slash, directly followed by the
RFC-2253 encoded DN of the subject. Note that you can't use the
string printed by gpgsm --list-keys because that one has been
reordered and modified for better readability; use --with-colons
to print the raw (but standard escaped) RFC-2253 string.

/CN=Heinrich Heine,O=Poets,L=Paris,C=FR

By exact match on the issuer's DN.
This is indicated by a leading hash mark, directly followed by a
slash and then directly followed by the RFC-2253 encoded DN of
the issuer. This should return the Root cert of the issuer.
See note above.

#/CN=Root Cert,O=Poets,L=Paris,C=FR

By exact match on serial number and issuer's DN.
This is indicated by a hash mark, followed by the hexadecimal
representation of the serial number, then followed by a slash
and the RFC-2253 encoded DN of the issuer. See note above.

#4F03/CN=Root Cert,O=Poets,L=Paris,C=FR

By keygrip.
This is indicated by an ampersand followed by the 40 hex digits
of a keygrip. gpgsm prints the keygrip when using the command
--dump-cert.

&D75F22C3F86E355877348498CDC92BD21010A480

By substring match.
This is the default mode but applications may want to explicitly
indicate this by putting the asterisk in front. Match is not
case sensitive.

Heine
*Heine

. and + prefixes
These prefixes are reserved for looking up mails anchored at the
end and for a word search mode. They are not yet implemented
and using them is undefined.

Please note that we have reused the hash mark identifier which
was used in old GnuPG versions to indicate the so called local-
id. It is not anymore used and there should be no conflict when
used with X.509 stuff.

Using the RFC-2253 format of DNs has the drawback that it is not
possible to map them back to the original encoding, however we
don't have to do this because our key database stores this en-
coding as meta data.

FILTER EXPRESSIONS
The options --import-filter and --export-filter use expressions with
this syntax (square brackets indicate an optional part and curly braces
a repetition, white space between the elements are allowed):

[lc] {[{flag}] PROPNAME op VALUE [lc]}

The name of a property (PROPNAME) may only consist of letters, digits
and underscores. The description for the filter type describes which
properties are defined. If an undefined property is used it evaluates
to the empty string. Unless otherwise noted, the VALUE must always be
given and may not be the empty string. No quoting is defined for the
value, thus the value may not contain the strings && or ||, which are
used as logical connection operators. The flag -- can be used to re-
move this restriction.

Numerical values are computed as long int; standard C notation applies.
lc is the logical connection operator; either && for a conjunction or
|| for a disjunction. A conjunction is assumed at the begin of an ex-
pression. Conjunctions have higher precedence than disjunctions. If
VALUE starts with one of the characters used in any op a space after
the op is required.

The supported operators (op) are:

=~ Substring must match.

!~ Substring must not match.

= The full string must match.

<> The full string must not match.

== The numerical value must match.

!= The numerical value must not match.

<= The numerical value of the field must be LE than the value.

< The numerical value of the field must be LT than the value.

> The numerical value of the field must be GT than the value.

>= The numerical value of the field must be GE than the value.

-le The string value of the field must be less or equal than the
value.

-lt The string value of the field must be less than the value.

-gt The string value of the field must be greater than the value.

-ge The string value of the field must be greater or equal than the
value.

-n True if value is not empty (no value allowed).

-z True if value is empty (no value allowed).

-t Alias for "PROPNAME != 0" (no value allowed).

-f Alias for "PROPNAME == 0" (no value allowed).

Values for flag must be space separated. The supported flags are:

-- VALUE spans to the end of the expression.

-c The string match in this part is done case-sensitive.

The filter options concatenate several specifications for a filter of
the same type. For example the four options in this example:

--import-filter keep-uid="uid =~ Alfa"
--import-filter keep-uid="&& uid !~ Test"
--import-filter keep-uid="|| uid =~ Alpha"
--import-filter keep-uid="uid !~ Test"

which is equivalent to

--import-filter \
keep-uid="uid =~ Alfa" && uid !~ Test" || uid =~ Alpha" && "uid !~ Test"

imports only the user ids of a key containing the strings "Alfa" or
"Alpha" but not the string "test".

TRUST VALUES
Trust values are used to indicate ownertrust and validity of keys and
user IDs. They are displayed with letters or strings:

-
unknown
No ownertrust assigned / not yet calculated.

e
expired

Trust calculation has failed; probably due to an expired key.

q
undefined, undef
Not enough information for calculation.

n
never Never trust this key.

m
marginal
Marginally trusted.

f
full Fully trusted.

u
ultimate
Ultimately trusted.

r
revoked
For validity only: the key or the user ID has been revoked.

?
err The program encountered an unknown trust value.

FILES
There are a few configuration files to control certain aspects of gpg's
operation. Unless noted, they are expected in the current home direc-
tory (see: [option --homedir]).

gpg.conf
This is the standard configuration file read by gpg on startup.
It may contain any valid long option; the leading two dashes may
not be entered and the option may not be abbreviated. This de-
fault name may be changed on the command line (see: [gpg-option
--options]). You should backup this file.

Note that on larger installations, it is useful to put predefined files
into the directory '/etc/skel/.gnupg' so that newly created users start
up with a working configuration. For existing users a small helper
script is provided to create these files (see: [addgnupghome]).

For internal purposes gpg creates and maintains a few other files; They
all live in the current home directory (see: [option --homedir]). Only
the gpg program may modify these files.

~/.gnupg
This is the default home directory which is used if neither the
environment variable GNUPGHOME nor the option --homedir is
given.

~/.gnupg/pubring.gpg
The public keyring. You should backup this file.

~/.gnupg/pubring.gpg.lock
The lock file for the public keyring.

~/.gnupg/pubring.kbx
The public keyring using a different format. This file is
shared with gpgsm. You should backup this file.

~/.gnupg/pubring.kbx.lock
The lock file for 'pubring.kbx'.

~/.gnupg/secring.gpg
A secret keyring as used by GnuPG versions before 2.1. It is
not used by GnuPG 2.1 and later.

~/.gnupg/secring.gpg.lock
The lock file for the secret keyring.

~/.gnupg/.gpg-v21-migrated
File indicating that a migration to GnuPG 2.1 has been done.

~/.gnupg/trustdb.gpg
The trust database. There is no need to backup this file; it is
better to backup the ownertrust values (see: [option --export-
ownertrust]).

~/.gnupg/trustdb.gpg.lock
The lock file for the trust database.

~/.gnupg/random_seed
A file used to preserve the state of the internal random pool.

~/.gnupg/openpgp-revocs.d/
This is the directory where gpg stores pre-generated revocation
certificates. The file name corresponds to the OpenPGP finger-
print of the respective key. It is suggested to backup those
certificates and if the primary private key is not stored on the
disk to move them to an external storage device. Anyone who can
access theses files is able to revoke the corresponding key.
You may want to print them out. You should backup all files in
this directory and take care to keep this backup closed away.

Operation is further controlled by a few environment variables:

HOME Used to locate the default home directory.

GNUPGHOME
If set directory used instead of "~/.gnupg".

GPG_AGENT_INFO
This variable is obsolete; it was used by GnuPG versions before
2.1.

PINENTRY_USER_DATA
This value is passed via gpg-agent to pinentry. It is useful to
convey extra information to a custom pinentry.

COLUMNS
LINES Used to size some displays to the full size of the screen.

LANGUAGE
Apart from its use by GNU, it is used in the W32 version to
override the language selection done through the Registry. If
used and set to a valid and available language name (langid),
the file with the translation is loaded from
gpgdir/gnupg.nls/langid.mo. Here gpgdir is the directory out of
which the gpg binary has been loaded. If it can't be loaded the
Registry is tried and as last resort the native Windows locale
system is used.

When calling the gpg-agent component gpg sends a set of environment
variables to gpg-agent. The names of these variables can be listed us-
ing the command:

gpg-connect-agent 'getinfo std_env_names' /bye | awk '$1=="D" {print $2}'

BUGS
On older systems this program should be installed as setuid(root). This
is necessary to lock memory pages. Locking memory pages prevents the
operating system from writing memory pages (which may contain
passphrases or other sensitive material) to disk. If you get no warning
message about insecure memory your operating system supports locking
without being root. The program drops root privileges as soon as locked
memory is allocated.

Note also that some systems (especially laptops) have the ability to
``suspend to disk'' (also known as ``safe sleep'' or ``hibernate'').
This writes all memory to disk before going into a low power or even
powered off mode. Unless measures are taken in the operating system to
protect the saved memory, passphrases or other sensitive material may
be recoverable from it later.

Before you report a bug you should first search the mailing list ar-
chives for similar problems and second check whether such a bug has al-
ready been reported to our bug tracker at https://bugs.gnupg.org.

SEE ALSO
gpgv(1), gpgsm(1), gpg-agent(1)

The full documentation for this tool is maintained as a Texinfo manual.
If GnuPG and the info program are properly installed at your site, the
command

info gnupg

should give you access to the complete manual including a menu struc-
ture and an index.

GnuPG 2.2.19 2019-11-23 GPG(1)

gpg

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