PKEYUTL(1SSL) OpenSSL PKEYUTL(1SSL)
openssl-pkeyutl, pkeyutl - public key algorithm utility
openssl pkeyutl [-help] [-in file] [-out file] [-sigfile file] [-inkey
file] [-keyform PEM|DER|ENGINE] [-passin arg] [-peerkey file]
[-peerform PEM|DER|ENGINE] [-pubin] [-certin] [-rev] [-sign] [-verify]
[-verifyrecover] [-encrypt] [-decrypt] [-derive] [-kdf algorithm]
[-kdflen length] [-pkeyopt opt:value] [-hexdump] [-asn1parse] [-rand
file...] [-writerand file] [-engine id] [-engine_impl]
The pkeyutl command can be used to perform low level public key
operations using any supported algorithm.
Print out a usage message.
This specifies the input filename to read data from or standard
input if this option is not specified.
Specifies the output filename to write to or standard output by
Signature file, required for verify operations only
The input key file, by default it should be a private key.
The key format PEM, DER or ENGINE. Default is PEM.
The input key password source. For more information about the
format of arg see the PASS PHRASE ARGUMENTS section in openssl(1).
The peer key file, used by key derivation (agreement) operations.
The peer key format PEM, DER or ENGINE. Default is PEM.
The input file is a public key.
The input is a certificate containing a public key.
Reverse the order of the input buffer. This is useful for some
libraries (such as CryptoAPI) which represent the buffer in little
Sign the input data (which must be a hash) and output the signed
result. This requires a private key.
Verify the input data (which must be a hash) against the signature
file and indicate if the verification succeeded or failed.
Verify the input data (which must be a hash) and output the
Encrypt the input data using a public key.
Decrypt the input data using a private key.
Derive a shared secret using the peer key.
Use key derivation function algorithm. The supported algorithms
are at present TLS1-PRF and HKDF. Note: additional parameters and
the KDF output length will normally have to be set for this to
work. See EVP_PKEY_CTX_set_hkdf_md(3) and
EVP_PKEY_CTX_set_tls1_prf_md(3) for the supported string parameters
of each algorithm.
Set the output length for KDF.
Public key options specified as opt:value. See NOTES below for more
hex dump the output data.
Parse the ASN.1 output data, this is useful when combined with the
-verifyrecover option when an ASN1 structure is signed.
A file or files containing random data used to seed the random
number generator. Multiple files can be specified separated by an
OS-dependent character. The separator is ; for MS-Windows, , for
OpenVMS, and : for all others.
Writes random data to the specified file upon exit. This can be
used with a subsequent -rand flag.
Specifying an engine (by its unique id string) will cause pkeyutl
to attempt to obtain a functional reference to the specified
engine, thus initialising it if needed. The engine will then be set
as the default for all available algorithms.
When used with the -engine option, it specifies to also use engine
id for crypto operations.
The operations and options supported vary according to the key
algorithm and its implementation. The OpenSSL operations and options
are indicated below.
Unless otherwise mentioned all algorithms support the digest:alg option
which specifies the digest in use for sign, verify and verifyrecover
operations. The value alg should represent a digest name as used in
the EVP_get_digestbyname() function for example sha1. This value is not
used to hash the input data. It is used (by some algorithms) for
sanity-checking the lengths of data passed in to the pkeyutl and for
creating the structures that make up the signature (e.g. DigestInfo in
RSASSA PKCS#1 v1.5 signatures).
This utility does not hash the input data but rather it will use the
data directly as input to the signature algorithm. Depending on the key
type, signature type, and mode of padding, the maximum acceptable
lengths of input data differ. The signed data can't be longer than the
key modulus with RSA. In case of ECDSA and DSA the data shouldn't be
longer than the field size, otherwise it will be silently truncated to
the field size. In any event the input size must not be larger than the
largest supported digest size.
In other words, if the value of digest is sha1 the input should be the
20 bytes long binary encoding of the SHA-1 hash function output.
The Ed25519 and Ed448 signature algorithms are not supported by this
utility. They accept non-hashed input, but this utility can only be
used to sign hashed input.
The RSA algorithm generally supports the encrypt, decrypt, sign, verify
and verifyrecover operations. However, some padding modes support only
a subset of these operations. The following additional pkeyopt values
This sets the RSA padding mode. Acceptable values for mode are
pkcs1 for PKCS#1 padding, sslv23 for SSLv23 padding, none for no
padding, oaep for OAEP mode, x931 for X9.31 mode and pss for PSS.
In PKCS#1 padding if the message digest is not set then the
supplied data is signed or verified directly instead of using a
DigestInfo structure. If a digest is set then the a DigestInfo
structure is used and its the length must correspond to the digest
For oaep mode only encryption and decryption is supported.
For x931 if the digest type is set it is used to format the block
data otherwise the first byte is used to specify the X9.31 digest
ID. Sign, verify and verifyrecover are can be performed in this
For pss mode only sign and verify are supported and the digest type
must be specified.
For pss mode only this option specifies the salt length. Three
special values are supported: "digest" sets the salt length to the
digest length, "max" sets the salt length to the maximum
permissible value. When verifying "auto" causes the salt length to
be automatically determined based on the PSS block structure.
For PSS and OAEP padding sets the MGF1 digest. If the MGF1 digest
is not explicitly set in PSS mode then the signing digest is used.
The RSA-PSS algorithm is a restricted version of the RSA algorithm
which only supports the sign and verify operations with PSS padding.
The following additional pkeyopt values are supported:
rsa_padding_mode:mode, rsa_pss_saltlen:len, rsa_mgf1_md:digest
These have the same meaning as the RSA algorithm with some
additional restrictions. The padding mode can only be set to pss
which is the default value.
If the key has parameter restrictions than the digest, MGF1 digest
and salt length are set to the values specified in the parameters.
The digest and MG cannot be changed and the salt length cannot be
set to a value less than the minimum restriction.
The DSA algorithm supports signing and verification operations only.
Currently there are no additional options other than digest. Only the
SHA1 digest can be used and this digest is assumed by default.
The DH algorithm only supports the derivation operation and no
The EC algorithm supports sign, verify and derive operations. The sign
and verify operations use ECDSA and derive uses ECDH. Currently there
are no additional options other than digest. Only the SHA1 digest can
be used and this digest is assumed by default.
X25519 and X448 ALGORITHMS
The X25519 and X448 algorithms support key derivation only. Currently
there are no additional options.
Sign some data using a private key:
openssl pkeyutl -sign -in file -inkey key.pem -out sig
Recover the signed data (e.g. if an RSA key is used):
openssl pkeyutl -verifyrecover -in sig -inkey key.pem
Verify the signature (e.g. a DSA key):
openssl pkeyutl -verify -in file -sigfile sig -inkey key.pem
Sign data using a message digest value (this is currently only valid
openssl pkeyutl -sign -in file -inkey key.pem -out sig -pkeyopt digest:sha256
Derive a shared secret value:
openssl pkeyutl -derive -inkey key.pem -peerkey pubkey.pem -out secret
Hexdump 48 bytes of TLS1 PRF using digest SHA256 and shared secret and
seed consisting of the single byte 0xFF:
openssl pkeyutl -kdf TLS1-PRF -kdflen 48 -pkeyopt md:SHA256 \
-pkeyopt hexsecret:ff -pkeyopt hexseed:ff -hexdump
genpkey(1), pkey(1), rsautl(1) dgst(1), rsa(1), genrsa(1),
Copyright 2006-2018 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the OpenSSL license (the "License"). You may not use
this file except in compliance with the License. You can obtain a copy
in the file LICENSE in the source distribution or at
1.1.1 2022-07-04 PKEYUTL(1SSL)
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