5 pkeyutl - public key algorithm utility
15 [B<-keyform PEM|DER|ENGINE>]
18 [B<-peerform PEM|DER|ENGINE>]
30 [B<-pkeyopt opt:value>]
38 The B<pkeyutl> command can be used to perform public key operations using
39 any supported algorithm.
47 Print out a usage message.
51 This specifies the input filename to read data from or standard input
52 if this option is not specified.
54 =item B<-out filename>
56 specifies the output filename to write to or standard output by
59 =item B<-sigfile file>
61 Signature file, required for B<verify> operations only
65 the input key file, by default it should be a private key.
67 =item B<-keyform PEM|DER|ENGINE>
69 the key format PEM, DER or ENGINE. Default is PEM.
73 the input key password source. For more information about the format of B<arg>
74 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
77 =item B<-peerkey file>
79 the peer key file, used by key derivation (agreement) operations.
81 =item B<-peerform PEM|DER|ENGINE>
83 the peer key format PEM, DER or ENGINE. Default is PEM.
87 the input file is a public key.
91 the input is a certificate containing a public key.
95 reverse the order of the input buffer. This is useful for some libraries
96 (such as CryptoAPI) which represent the buffer in little endian format.
100 sign the input data and output the signed result. This requires
105 verify the input data against the signature file and indicate if the
106 verification succeeded or failed.
108 =item B<-verifyrecover>
110 verify the input data and output the recovered data.
114 encrypt the input data using a public key.
118 decrypt the input data using a private key.
122 derive a shared secret using the peer key.
124 =item B<-kdf algorithm>
126 Use key derivation function B<algorithm>. The supported algorithms are
127 at present B<TLS1-PRF> and B<HKDF>.
128 Note: additional parameters and the KDF output length will normally have to be
129 set for this to work.
130 See L<EVP_PKEY_CTX_set_hkdf_md(3)> and L<EVP_PKEY_CTX_set_tls1_prf_md(3)>
131 for the supported string parameters of each algorithm.
133 =item B<-kdflen length>
135 Set the output length for KDF.
137 =item B<-pkeyopt opt:value>
139 Public key options specified as opt:value. See NOTES below for more details.
143 hex dump the output data.
147 asn1parse the output data, this is useful when combined with the
148 B<-verifyrecover> option when an ASN1 structure is signed.
152 specifying an engine (by its unique B<id> string) will cause B<pkeyutl>
153 to attempt to obtain a functional reference to the specified engine,
154 thus initialising it if needed. The engine will then be set as the default
155 for all available algorithms.
157 =item B<-engine_impl>
159 When used with the B<-engine> option, it specifies to also use
160 engine B<id> for crypto operations.
166 The operations and options supported vary according to the key algorithm
167 and its implementation. The OpenSSL operations and options are indicated below.
169 Unless otherwise mentioned all algorithms support the B<digest:alg> option
170 which specifies the digest in use for sign, verify and verifyrecover operations.
171 The value B<alg> should represent a digest name as used in the
172 EVP_get_digestbyname() function for example B<sha1>.
173 This value is used only for sanity-checking the lengths of data passed in to
174 the B<pkeyutl> and for creating the structures that make up the signature
175 (e.g. B<DigestInfo> in RSASSA PKCS#1 v1.5 signatures).
176 In case of RSA, ECDSA and DSA signatures, this utility
177 will not perform hashing on input data but rather use the data directly as
178 input of signature algorithm. Depending on key type, signature type and mode
179 of padding, the maximum acceptable lengths of input data differ. In general,
180 with RSA the signed data can't be longer than the key modulus, in case of ECDSA
181 and DSA the data shouldn't be longer than field size, otherwise it will be
182 silently truncated to field size.
184 In other words, if the value of digest is B<sha1> the input should be 20 bytes
185 long binary encoding of SHA-1 hash function output.
189 The RSA algorithm generally supports the encrypt, decrypt, sign,
190 verify and verifyrecover operations. However, some padding modes
191 support only a subset of these operations. The following additional
192 B<pkeyopt> values are supported:
196 =item B<rsa_padding_mode:mode>
198 This sets the RSA padding mode. Acceptable values for B<mode> are B<pkcs1> for
199 PKCS#1 padding, B<sslv23> for SSLv23 padding, B<none> for no padding, B<oaep>
200 for B<OAEP> mode, B<x931> for X9.31 mode and B<pss> for PSS.
202 In PKCS#1 padding if the message digest is not set then the supplied data is
203 signed or verified directly instead of using a B<DigestInfo> structure. If a
204 digest is set then the a B<DigestInfo> structure is used and its the length
205 must correspond to the digest type.
207 For B<oaep> mode only encryption and decryption is supported.
209 For B<x931> if the digest type is set it is used to format the block data
210 otherwise the first byte is used to specify the X9.31 digest ID. Sign,
211 verify and verifyrecover are can be performed in this mode.
213 For B<pss> mode only sign and verify are supported and the digest type must be
216 =item B<rsa_pss_saltlen:len>
218 For B<pss> mode only this option specifies the salt length. Three special
219 values are supported: "digest" sets the salt length to the digest length,
220 "max" sets the salt length to the maximum permissible value. When verifying
221 "auto" causes the salt length to be automatically determined based on the
222 B<PSS> block structure.
224 =item B<rsa_mgf1_md:digest>
226 For PSS and OAEP padding sets the MGF1 digest. If the MGF1 digest is not
227 explicitly set in PSS mode then the signing digest is used.
231 =head1 RSA-PSS ALGORITHM
233 The RSA-PSS algorithm is a restricted version of the RSA algorithm which only
234 supports the sign and verify operations with PSS padding. The following
235 additional B<pkeyopt> values are supported:
239 =item B<rsa_padding_mode:mode>, B<rsa_pss_saltlen:len>, B<rsa_mgf1_md:digest>
241 These have the same meaning as the B<RSA> algorithm with some additional
242 restrictions. The padding mode can only be set to B<pss> which is the
245 If the key has parameter restrictions than the digest, MGF1
246 digest and salt length are set to the values specified in the parameters.
247 The digest and MG cannot be changed and the salt length cannot be set to a
248 value less than the minimum restriction.
254 The DSA algorithm supports signing and verification operations only. Currently
255 there are no additional options other than B<digest>. Only the SHA1
256 digest can be used and this digest is assumed by default.
260 The DH algorithm only supports the derivation operation and no additional
265 The EC algorithm supports sign, verify and derive operations. The sign and
266 verify operations use ECDSA and derive uses ECDH. Currently there are no
267 additional options other than B<digest>. Only the SHA1 digest can be used and
268 this digest is assumed by default.
270 =head1 X25519 ALGORITHM
272 The X25519 algorithm supports key derivation only. Currently there are no
277 Sign some data using a private key:
279 openssl pkeyutl -sign -in file -inkey key.pem -out sig
281 Recover the signed data (e.g. if an RSA key is used):
283 openssl pkeyutl -verifyrecover -in sig -inkey key.pem
285 Verify the signature (e.g. a DSA key):
287 openssl pkeyutl -verify -in file -sigfile sig -inkey key.pem
289 Sign data using a message digest value (this is currently only valid for RSA):
291 openssl pkeyutl -sign -in file -inkey key.pem -out sig -pkeyopt digest:sha256
293 Derive a shared secret value:
295 openssl pkeyutl -derive -inkey key.pem -peerkey pubkey.pem -out secret
297 Hexdump 48 bytes of TLS1 PRF using digest B<SHA256> and shared secret and
298 seed consisting of the single byte 0xFF:
300 openssl pkeyutl -kdf TLS1-PRF -kdflen 48 -pkeyopt md:SHA256 \
301 -pkeyopt hexsecret:ff -pkeyopt hexseed:ff -hexdump
305 L<genpkey(1)>, L<pkey(1)>, L<rsautl(1)>
306 L<dgst(1)>, L<rsa(1)>, L<genrsa(1)>,
307 L<EVP_PKEY_CTX_set_hkdf_md(3)>, L<EVP_PKEY_CTX_set_tls1_prf_md(3)>
311 Copyright 2006-2016 The OpenSSL Project Authors. All Rights Reserved.
313 Licensed under the OpenSSL license (the "License"). You may not use
314 this file except in compliance with the License. You can obtain a copy
315 in the file LICENSE in the source distribution or at
316 L<https://www.openssl.org/source/license.html>.