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PKEYUTL(1)			    OpenSSL			    PKEYUTL(1)

       openssl-pkeyutl,	pkeyutl	- public key algorithm utility

       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]

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

	   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

       -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 "Pass Phrase Options" 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.

	   The input file is a public key.

	   The input is	a certificate containing a public key.

	   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	the input data (which must be a	hash) and output the signed
	   result. This	requires a private key.

	   Verify the input data (which	must be	a hash)	against	the signature
	   file	and indicate if	the verification succeeded or failed.

	   Verify the input data (which	must be	a hash)	and output the
	   recovered data.

	   Encrypt the input data using	a public key.

	   Decrypt the input data using	a private key.

	   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

	   hex dump the	output data.

	   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.

	   When	used with the -engine option, it specifies to also use engine
	   id for crypto operations.

       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.

       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:

	   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

	   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

	   For pss mode	only sign and verify are supported and the digest type
	   must	be specified.

	   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.

	   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.

       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.

       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.

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

       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.

       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

       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 2006-2021 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

1.1.1k				  2021-03-25			    PKEYUTL(1)


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