OPENSSL-PKEYUTL(1SSL) OpenSSL OPENSSL-PKEYUTL(1SSL)
NAME
openssl-pkeyutl - public key algorithm command
SYNOPSIS
openssl pkeyutl [-help] [-in file] [-rawin] [-digest algorithm] [-out
file] [-sigfile file] [-inkey filename|uri] [-keyform
DER|PEM|P12|ENGINE] [-passin arg] [-peerkey file] [-peerform
DER|PEM|P12|ENGINE] [-pubin] [-certin] [-rev] [-sign] [-verify]
[-verifyrecover] [-encrypt] [-decrypt] [-derive] [-kdf algorithm]
[-kdflen length] [-pkeyopt opt:value] [-pkeyopt_passin opt[:passarg]]
[-hexdump] [-asn1parse] [-engine id] [-engine_impl] [-rand files]
[-writerand file] [-provider name] [-provider-path path] [-propquery
propq] [-config configfile]
DESCRIPTION
This command can be used to perform low-level public key operations
using any supported algorithm.
OPTIONS
-help
Print out a usage message.
-in filename
This specifies the input filename to read data from or standard
input if this option is not specified.
-rawin
This indicates that the input data is raw data, which is not hashed
by any message digest algorithm. The user can specify a digest
algorithm by using the -digest option. This option can only be used
with -sign and -verify and must be used with the Ed25519 and Ed448
algorithms.
-digest algorithm
This specifies the digest algorithm which is used to hash the input
data before signing or verifying it with the input key. This option
could be omitted if the signature algorithm does not require one
(for instance, EdDSA). If this option is omitted but the signature
algorithm requires one, a default value will be used. For signature
algorithms like RSA, DSA and ECDSA, SHA-256 will be the default
digest algorithm. For SM2, it will be SM3. If this option is
present, then the -rawin option must be also specified.
-out filename
Specifies the output filename to write to or standard output by
default.
-sigfile file
Signature file, required for -verify operations only
-inkey filename|uri
The input key, by default it should be a private key.
-keyform DER|PEM|P12|ENGINE
The key format; unspecified by default. See
openssl-format-options(1) for details.
-passin arg
The input key password source. For more information about the
format of arg see openssl-passphrase-options(1).
-peerkey file
The peer key file, used by key derivation (agreement) operations.
-peerform DER|PEM|P12|ENGINE
The peer key format; unspecified by default. See
openssl-format-options(1) for details.
-pubin
The input file is a public key.
-certin
The input is a certificate containing a public key.
-rev
Reverse the order of the input buffer. This is useful for some
libraries (such as CryptoAPI) which represent the buffer in little
endian format.
-sign
Sign the input data (which must be a hash) and output the signed
result. This requires a private key.
-verify
Verify the input data (which must be a hash) against the signature
file and indicate if the verification succeeded or failed.
-verifyrecover
Verify the input data (which must be a hash) and output the
recovered data.
-encrypt
Encrypt the input data using a public key.
-decrypt
Decrypt the input data using a private key.
-derive
Derive a shared secret using the peer key.
-kdf algorithm
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.
-kdflen length
Set the output length for KDF.
-pkeyopt opt:value
Public key options specified as opt:value. See NOTES below for more
details.
-pkeyopt_passin opt[:passarg]
Allows reading a public key option opt from stdin or a password
source. If only opt is specified, the user will be prompted to
enter a password on stdin. Alternatively, passarg can be specified
which can be any value supported by openssl-passphrase-options(1).
-hexdump
hex dump the output data.
-asn1parse
Parse the ASN.1 output data, this is useful when combined with the
-verifyrecover option when an ASN1 structure is signed.
-engine id
See "Engine Options" in openssl(1). This option is deprecated.
-engine_impl
When used with the -engine option, it specifies to also use engine
id for crypto operations.
-rand files, -writerand file
See "Random State Options" in openssl(1) for details.
-provider name
-provider-path path
-propquery propq
See "Provider Options" in openssl(1), provider(7), and property(7).
-config configfile
See "Configuration Option" in openssl(1).
NOTES
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 and for creating the
structures that make up the signature (e.g. DigestInfo in RSASSA PKCS#1
v1.5 signatures).
This command does not hash the input data (except where -rawin is used)
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.
RSA ALGORITHM
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
are supported:
rsa_padding_mode:mode
This sets the RSA padding mode. Acceptable values for mode are
pkcs1 for PKCS#1 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 DigestInfo
structure is used and its length must correspond to the digest
type.
Note, for pkcs1 padding, as a protection against Bleichenbacher
attack, the decryption will not fail in case of padding check
failures. Use none and manual inspection of the decrypted message
to verify if the decrypted value has correct PKCS#1 v1.5 padding.
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
mode.
For pss mode only sign and verify are supported and the digest type
must be specified.
rsa_pss_saltlen:len
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.
rsa_mgf1_md:digest
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.
rsa_oaep_md:digest
Sets the digest used for the OAEP hash function. If not explicitly
set then SHA1 is used.
rsa_pkcs1_implicit_rejection:flag
Disables (when set to 0) or enables (when set to 1) the use of
implicit rejection with PKCS#1 v1.5 decryption. When enabled (the
default), as a protection against Bleichenbacher attack, the
library will generate a deterministic random plaintext that it will
return to the caller in case of padding check failure. When
disabled, it's the callers' responsibility to handle the returned
errors in a side-channel free manner.
RSA-PSS ALGORITHM
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.
DSA ALGORITHM
The DSA algorithm supports signing and verification operations only.
Currently there are no additional -pkeyopt options other than digest.
The SHA1 digest is assumed by default.
DH ALGORITHM
The DH algorithm only supports the derivation operation and no
additional -pkeyopt options.
EC ALGORITHM
The EC algorithm supports sign, verify and derive operations. The sign
and verify operations use ECDSA and derive uses ECDH. SHA1 is assumed
by default for the -pkeyopt digest option.
X25519 AND X448 ALGORITHMS
The X25519 and X448 algorithms support key derivation only. Currently
there are no additional options.
ED25519 AND ED448 ALGORITHMS
These algorithms only support signing and verifying. OpenSSL only
implements the "pure" variants of these algorithms so raw data can be
passed directly to them without hashing them first. The option -rawin
must be used with these algorithms with no -digest specified.
Additionally OpenSSL only supports "oneshot" operation with these
algorithms. This means that the entire file to be signed/verified must
be read into memory before processing it. Signing or Verifying very
large files should be avoided. Additionally the size of the file must
be known for this to work. If the size of the file cannot be determined
(for example if the input is stdin) then the sign or verify operation
will fail.
SM2
The SM2 algorithm supports sign, verify, encrypt and decrypt
operations. For the sign and verify operations, SM2 requires an
Distinguishing ID string to be passed in. The following -pkeyopt value
is supported:
distid:string
This sets the ID string used in SM2 sign or verify operations.
While verifying an SM2 signature, the ID string must be the same
one used when signing the data. Otherwise the verification will
fail.
hexdistid:hex_string
This sets the ID string used in SM2 sign or verify operations.
While verifying an SM2 signature, the ID string must be the same
one used when signing the data. Otherwise the verification will
fail. The ID string provided with this option should be a valid
hexadecimal value.
EXAMPLES
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
for RSA):
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
Derive a key using scrypt where the password is read from command line:
openssl pkeyutl -kdf scrypt -kdflen 16 -pkeyopt_passin pass \
-pkeyopt hexsalt:aabbcc -pkeyopt N:16384 -pkeyopt r:8 -pkeyopt p:1
Derive using the same algorithm, but read key from environment variable
MYPASS:
openssl pkeyutl -kdf scrypt -kdflen 16 -pkeyopt_passin pass:env:MYPASS \
-pkeyopt hexsalt:aabbcc -pkeyopt N:16384 -pkeyopt r:8 -pkeyopt p:1
Sign some data using an SM2(7) private key and a specific ID:
openssl pkeyutl -sign -in file -inkey sm2.key -out sig -rawin -digest sm3 \
-pkeyopt distid:someid
Verify some data using an SM2(7) certificate and a specific ID:
openssl pkeyutl -verify -certin -in file -inkey sm2.cert -sigfile sig \
-rawin -digest sm3 -pkeyopt distid:someid
Decrypt some data using a private key with OAEP padding using SHA256:
openssl pkeyutl -decrypt -in file -inkey key.pem -out secret \
-pkeyopt rsa_padding_mode:oaep -pkeyopt rsa_oaep_md:sha256
SEE ALSO
openssl(1), openssl-genpkey(1), openssl-pkey(1), openssl-rsautl(1)
openssl-dgst(1), openssl-rsa(1), openssl-genrsa(1), openssl-kdf(1)
EVP_PKEY_CTX_set_hkdf_md(3), EVP_PKEY_CTX_set_tls1_prf_md(3),
HISTORY
The -engine option was deprecated in OpenSSL 3.0.
COPYRIGHT
Copyright 2006-2021 The OpenSSL Project Authors. All Rights Reserved.
Licensed under the Apache License 2.0 (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
<https://www.openssl.org/source/license.html>.
3.0.13 2025-09-18 OPENSSL-PKEYUTL(1SSL)
Generated by dwww version 1.16 on Tue Dec 16 15:00:11 CET 2025.