man > openssl-pkeyutl(1)

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                                       2026-07-29                        OPENSSL-PKEYUTL(1SSL)