/usr/man/cat.1/pkeyutl.1.Z
NAME
openssl-pkeyutl, 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 for-
mat 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 algo-
rithm 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
used only 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). In case of RSA,
ECDSA and DSA signatures, this utility will not perform hashing on
input data but rather use the data directly as input of signature algo-
rithm. Depending on key type, signature type and mode of padding, the
maximum acceptable lengths of input data differ. In general, with RSA
the signed data can't be longer than the key modulus, in case of ECDSA
and DSA the data shouldn't be longer than field size, otherwise it will
be silently truncated to field size.
In other words, if the value of digest is sha1 the input should be 20
bytes long binary encoding of SHA-1 hash function output.
RSA ALGORITHM
The RSA algorithm supports encrypt, decrypt, sign, verify and verifyre-
cover 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 sup-
plied 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 spe-
cial values are supported: -1 sets the salt length to the digest
length. When signing -2 sets the salt length to the maximum permis-
sible value. When verifying -2 causes the salt length to be auto-
matically 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 addi-
tional 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)
1.0.2t 2019-09-10 PKEYUTL(1)
See also openssl-pkeyutl(1)
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