openssl command [ command_opts ] [ command_args ]
openssl list [ standard-commands | digest-commands | cipher-commands |
cipher-algorithms | digest-algorithms | public-key-algorithms]
openssl no-XXX [ arbitrary options ]
OpenSSL is a cryptography toolkit implementing the Secure Sockets Layer
(SSL v2/v3) and Transport Layer Security (TLS v1) network protocols and
related cryptography standards required by them.
The openssl program is a command line tool for using the various
cryptography functions of OpenSSL's crypto library from the shell. It
can be used for
o Creation and management of private keys, public keys and parameters
o Public key cryptographic operations
o Creation of X.509 certificates, CSRs and CRLs
o Calculation of Message Digests
o Encryption and Decryption with Ciphers
o SSL/TLS Client and Server Tests
o Handling of S/MIME signed or encrypted mail
o Time Stamp requests, generation and verification
The openssl program provides a rich variety of commands (command in the
SYNOPSIS above), each of which often has a wealth of options and
arguments (command_opts and command_args in the SYNOPSIS).
Many commands use an external configuration file for some or all of
their arguments and have a -config option to specify that file. The
environment variable OPENSSL_CONF can be used to specify the location
of the file. If the environment variable is not specified, then the
file is named openssl.cnf in the default certificate storage area,
whose value depends on the configuration flags specified when the
OpenSSL was built.
The list parameters standard-commands, digest-commands, and cipher-
commands output a list (one entry per line) of the names of all
standard commands, message digest commands, or cipher commands,
respectively, that are available in the present openssl utility.
The list parameters cipher-algorithms and digest-algorithms list all
cipher and message digest names, one entry per line. Aliases are listed
from => to
The list parameter public-key-algorithms lists all supported public key
The command no-XXX tests whether a command of the specified name is
available. If no command named XXX exists, it returns 0 (success) and
ca Certificate Authority (CA) Management.
Cipher Suite Description Determination.
cms CMS (Cryptographic Message Syntax) utility.
crl Certificate Revocation List (CRL) Management.
CRL to PKCS#7 Conversion.
Message Digest Calculation.
dh Diffie-Hellman Parameter Management. Obsoleted by dhparam.
Generation and Management of Diffie-Hellman Parameters. Superseded
by genpkey and pkeyparam.
dsa DSA Data Management.
DSA Parameter Generation and Management. Superseded by genpkey and
ec EC (Elliptic curve) key processing.
EC parameter manipulation and generation.
enc Encoding with Ciphers.
Engine (loadable module) information and manipulation.
Error Number to Error String Conversion.
Generation of Diffie-Hellman Parameters. Obsoleted by dhparam.
Generation of DSA Private Key from Parameters. Superseded by
genpkey and pkey.
Generation of Private Key or Parameters.
Generation of RSA Private Key. Superseded by genpkey.
PKCS#7 Data Management.
PKCS#8 format private key conversion tool.
Public and private key management.
Public key algorithm parameter management.
Public key algorithm cryptographic operation utility.
Generate pseudo-random bytes.
Create symbolic links to certificate and CRL files named by the
req PKCS#10 X.509 Certificate Signing Request (CSR) Management.
rsa RSA key management.
RSA utility for signing, verification, encryption, and decryption.
Superseded by pkeyutl.
This implements a generic SSL/TLS client which can establish a
transparent connection to a remote server speaking SSL/TLS. It's
intended for testing purposes only and provides only rudimentary
interface functionality but internally uses mostly all
functionality of the OpenSSL ssl library.
This implements a generic SSL/TLS server which accepts connections
from remote clients speaking SSL/TLS. It's intended for testing
purposes only and provides only rudimentary interface functionality
but internally uses mostly all functionality of the OpenSSL ssl
library. It provides both an own command line oriented protocol
for testing SSL functions and a simple HTTP response facility to
emulate an SSL/TLS-aware webserver.
SSL Connection Timer.
SSL Session Data Management.
S/MIME mail processing.
OpenSSL Version Information.
X.509 Certificate Data Management.
Message Digest Commands
md2 MD2 Digest
md5 MD5 Digest
sha SHA Digest
Encoding and Cipher Commands
bf bf-cbc bf-cfb bf-ecb bf-ofb
cast5-cbc cast5-cfb cast5-ecb cast5-ofb
des des-cbc des-cfb des-ecb des-ede des-ede-cbc des-ede-cfb des-ede-ofb
des3 desx des-ede3 des-ede3-cbc des-ede3-cfb des-ede3-ofb
idea idea-cbc idea-cfb idea-ecb idea-ofb
This section describes some common options with common behavior.
Provides a terse summary of all options.
Pass Phrase Options
Several commands accept password arguments, typically using -passin and
-passout for input and output passwords respectively. These allow the
password to be obtained from a variety of sources. Both of these
options take a single argument whose format is described below. If no
password argument is given and a password is required then the user is
prompted to enter one: this will typically be read from the current
terminal with echoing turned off.
The actual password is password. Since the password is visible to
utilities (like 'ps' under Unix) this form should only be used
where security is not important.
Obtain the password from the environment variable var. Since the
environment of other processes is visible on certain platforms
(e.g. ps under certain Unix OSes) this option should be used with
The first line of pathname is the password. If the same pathname
argument is supplied to -passin and -passout arguments then the
first line will be used for the input password and the next line
for the output password. pathname need not refer to a regular file:
it could for example refer to a device or named pipe.
Read the password from the file descriptor number. This can be used
to send the data via a pipe for example.
Read the password from standard input.
asn1parse(1), ca(1), ciphers(1), cms(1), config(5), crl(1),
crl2pkcs7(1), dgst(1), dhparam(1), dsa(1), dsaparam(1), ec(1),
ecparam(1), enc(1), engine(1), errstr(1), gendsa(1), genpkey(1),
genrsa(1), nseq(1), ocsp(1), passwd(1), pkcs12(1), pkcs7(1), pkcs8(1),
pkey(1), pkeyparam(1), pkeyutl(1), rand(1), rehash(1), req(1), rsa(1),
rsautl(1), s_client(1), s_server(1), s_time(1), sess_id(1), smime(1),
speed(1), spkac(1), ts(1), verify(1), version(1), x509(1), crypto(7),
The list-XXX-algorithms pseudo-commands were added in OpenSSL 1.0.0;
For notes on the availability of other commands, see their individual
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