Provided by: openssl_1.1.1f-1ubuntu2.23_amd64 
NAME
openssl-pkeyutl, pkeyutl - public key algorithm utility
SYNOPSIS
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]
DESCRIPTION
The pkeyutl 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.
-out filename
Specifies the output filename to write to or standard output by default.
-sigfile file
Signature file, required for verify operations only
-inkey file
The input key file, by default it should be a private key.
-keyform PEM|DER|ENGINE
The key format PEM, DER or ENGINE. Default is PEM.
-passin arg
The input key password source. For more information about the format of arg see the
PASS PHRASE ARGUMENTS section in openssl(1).
-peerkey file
The peer key file, used by key derivation (agreement) operations.
-peerform PEM|DER|ENGINE
The peer key format PEM, DER or ENGINE. Default is PEM.
-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.
-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.
-rand file...
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.
[-writerand file]
Writes random data to the specified file upon exit. This can be used with a
subsequent -rand flag.
-engine id
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.
-engine_impl
When used with the -engine option, it specifies to also use engine id for crypto
operations.
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 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.
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, 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 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_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.
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
SEE ALSO
genpkey(1), pkey(1), rsautl(1) dgst(1), rsa(1), genrsa(1), EVP_PKEY_CTX_set_hkdf_md(3),
EVP_PKEY_CTX_set_tls1_prf_md(3)
COPYRIGHT
Copyright 2006-2019 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 <https://www.openssl.org/source/license.html>.