NAME

       pkeyutl - public key algorithm utility

SYNOPSIS

       openssl pkeyutl [-in file] [-out file] [-sigfile file] [-inkey file] [-keyform PEM|DER] [-passin arg]
       [-peerkey file] [-peerform PEM|DER] [-pubin] [-certin] [-rev] [-sign] [-verify] [-verifyrecover]
       [-encrypt] [-decrypt] [-derive] [-pkeyopt opt:value] [-hexdump] [-asn1parse] [-engine id]

DESCRIPTION

       The pkeyutl command can be used to perform public key operations using any supported algorithm.

COMMAND OPTIONS

       -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.

       -inkey file
           the input key file, by default it should be a private key.

       -keyform PEM|DER
           the key format PEM, DER or ENGINE.

       -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
           the peer key format PEM, DER or ENGINE.

       -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.

       -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 and output the signed result. This requires a private key.

       -verify
           verify the input data against the signature file and indicate if the verification succeeded or
           failed.

       -verifyrecover
           verify the input data 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.

       -hexdump
           hex dump the output data.

       -asn1parse
           asn1parse the output data, this is useful when combined with the -verifyrecover option when an ASN1
           structure is signed.

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.

RSA ALGORITHM

       The RSA algorithm supports encrypt, decrypt, sign, verify and verifyrecover operations in general. Some
       padding modes only support some of these operations however.

       -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.

           For oeap 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. Two special values are supported: -1 sets
           the salt length to the digest length. When signing -2 sets the salt length to the maximum permissible
           value. When verifying -2 causes the salt length to be automatically determined based on the PSS block
           structure.

DSA ALGORITHM

       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.

DH ALGORITHM

       The DH algorithm only supports the derivation operation and no additional options.

EC ALGORITHM

       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.

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

SEE ALSO

       genpkey(1), pkey(1), rsautl(1) dgst(1), rsa(1), genrsa(1)