Provided by: openssl_3.3.1-2ubuntu2_amd64 
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
By default a private key is read from the key input. With this option a public key is
read instead. If the input contains no public key but a private key, its public part
is used.
-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 the 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 then 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 2006-2023 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>.