/usr/man/cat.1/pkeyutl.1
PKEYUTL(1) OpenSSL PKEYUTL(1)
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 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.
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-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. 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
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PKEYUTL(1) OpenSSL PKEYUTL(1)
algorithm. 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 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.
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PKEYUTL(1) OpenSSL PKEYUTL(1)
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)
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See also openssl-pkeyutl(1)
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