5 pkeyutl - public key algorithm utility
15 [B<-keyform PEM|DER|ENGINE>]
18 [B<-peerform PEM|DER|ENGINE>]
30 [B<-pkeyopt opt:value>]
40 The B<pkeyutl> command can be used to perform public key operations using
41 any supported algorithm.
49 Print out a usage message.
53 This specifies the input filename to read data from or standard input
54 if this option is not specified.
56 =item B<-out filename>
58 Specifies the output filename to write to or standard output by
61 =item B<-sigfile file>
63 Signature file, required for B<verify> operations only
67 The input key file, by default it should be a private key.
69 =item B<-keyform PEM|DER|ENGINE>
71 The key format PEM, DER or ENGINE. Default is PEM.
75 The input key password source. For more information about the format of B<arg>
76 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
78 =item B<-peerkey file>
80 The peer key file, used by key derivation (agreement) operations.
82 =item B<-peerform PEM|DER|ENGINE>
84 The peer key format PEM, DER or ENGINE. Default is PEM.
88 The input file is a public key.
92 The input is a certificate containing a public key.
96 Reverse the order of the input buffer. This is useful for some libraries
97 (such as CryptoAPI) which represent the buffer in little endian format.
101 Sign the input data and output the signed result. This requires
106 Verify the input data against the signature file and indicate if the
107 verification succeeded or failed.
109 =item B<-verifyrecover>
111 Verify the input data and output the recovered data.
115 Encrypt the input data using a public key.
119 Decrypt the input data using a private key.
123 Derive a shared secret using the peer key.
125 =item B<-kdf algorithm>
127 Use key derivation function B<algorithm>. The supported algorithms are
128 at present B<TLS1-PRF> and B<HKDF>.
129 Note: additional parameters and the KDF output length will normally have to be
130 set for this to work.
131 See L<EVP_PKEY_CTX_set_hkdf_md(3)> and L<EVP_PKEY_CTX_set_tls1_prf_md(3)>
132 for the supported string parameters of each algorithm.
134 =item B<-kdflen length>
136 Set the output length for KDF.
138 =item B<-pkeyopt opt:value>
140 Public key options specified as opt:value. See NOTES below for more details.
144 hex dump the output data.
148 Parse the ASN.1 output data, this is useful when combined with the
149 B<-verifyrecover> option when an ASN1 structure is signed.
151 =item B<-rand file...>
153 A file or files containing random data used to seed the random number
155 Multiple files can be specified separated by an OS-dependent character.
156 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
159 =item [B<-writerand file>]
161 Writes random data to the specified I<file> upon exit.
162 This can be used with a subsequent B<-rand> flag.
166 Specifying an engine (by its unique B<id> string) will cause B<pkeyutl>
167 to attempt to obtain a functional reference to the specified engine,
168 thus initialising it if needed. The engine will then be set as the default
169 for all available algorithms.
171 =item B<-engine_impl>
173 When used with the B<-engine> option, it specifies to also use
174 engine B<id> for crypto operations.
180 The operations and options supported vary according to the key algorithm
181 and its implementation. The OpenSSL operations and options are indicated below.
183 Unless otherwise mentioned all algorithms support the B<digest:alg> option
184 which specifies the digest in use for sign, verify and verifyrecover operations.
185 The value B<alg> should represent a digest name as used in the
186 EVP_get_digestbyname() function for example B<sha1>.
187 This value is used only for sanity-checking the lengths of data passed in to
188 the B<pkeyutl> and for creating the structures that make up the signature
189 (e.g. B<DigestInfo> in RSASSA PKCS#1 v1.5 signatures).
190 In case of RSA, ECDSA and DSA signatures, this utility
191 will not perform hashing on input data but rather use the data directly as
192 input of signature algorithm. Depending on key type, signature type and mode
193 of padding, the maximum acceptable lengths of input data differ. In general,
194 with RSA the signed data can't be longer than the key modulus, in case of ECDSA
195 and DSA the data shouldn't be longer than field size, otherwise it will be
196 silently truncated to field size.
198 In other words, if the value of digest is B<sha1> the input should be 20 bytes
199 long binary encoding of SHA-1 hash function output.
203 The RSA algorithm generally supports the encrypt, decrypt, sign,
204 verify and verifyrecover operations. However, some padding modes
205 support only a subset of these operations. The following additional
206 B<pkeyopt> values are supported:
210 =item B<rsa_padding_mode:mode>
212 This sets the RSA padding mode. Acceptable values for B<mode> are B<pkcs1> for
213 PKCS#1 padding, B<sslv23> for SSLv23 padding, B<none> for no padding, B<oaep>
214 for B<OAEP> mode, B<x931> for X9.31 mode and B<pss> for PSS.
216 In PKCS#1 padding if the message digest is not set then the supplied data is
217 signed or verified directly instead of using a B<DigestInfo> structure. If a
218 digest is set then the a B<DigestInfo> structure is used and its the length
219 must correspond to the digest type.
221 For B<oaep> mode only encryption and decryption is supported.
223 For B<x931> if the digest type is set it is used to format the block data
224 otherwise the first byte is used to specify the X9.31 digest ID. Sign,
225 verify and verifyrecover are can be performed in this mode.
227 For B<pss> mode only sign and verify are supported and the digest type must be
230 =item B<rsa_pss_saltlen:len>
232 For B<pss> mode only this option specifies the salt length. Three special
233 values are supported: "digest" sets the salt length to the digest length,
234 "max" sets the salt length to the maximum permissible value. When verifying
235 "auto" causes the salt length to be automatically determined based on the
236 B<PSS> block structure.
238 =item B<rsa_mgf1_md:digest>
240 For PSS and OAEP padding sets the MGF1 digest. If the MGF1 digest is not
241 explicitly set in PSS mode then the signing digest is used.
245 =head1 RSA-PSS ALGORITHM
247 The RSA-PSS algorithm is a restricted version of the RSA algorithm which only
248 supports the sign and verify operations with PSS padding. The following
249 additional B<pkeyopt> values are supported:
253 =item B<rsa_padding_mode:mode>, B<rsa_pss_saltlen:len>, B<rsa_mgf1_md:digest>
255 These have the same meaning as the B<RSA> algorithm with some additional
256 restrictions. The padding mode can only be set to B<pss> which is the
259 If the key has parameter restrictions than the digest, MGF1
260 digest and salt length are set to the values specified in the parameters.
261 The digest and MG cannot be changed and the salt length cannot be set to a
262 value less than the minimum restriction.
268 The DSA algorithm supports signing and verification operations only. Currently
269 there are no additional options other than B<digest>. Only the SHA1
270 digest can be used and this digest is assumed by default.
274 The DH algorithm only supports the derivation operation and no additional
279 The EC algorithm supports sign, verify and derive operations. The sign and
280 verify operations use ECDSA and derive uses ECDH. Currently there are no
281 additional options other than B<digest>. Only the SHA1 digest can be used and
282 this digest is assumed by default.
284 =head1 X25519 ALGORITHM
286 The X25519 algorithm supports key derivation only. Currently there are no
291 Sign some data using a private key:
293 openssl pkeyutl -sign -in file -inkey key.pem -out sig
295 Recover the signed data (e.g. if an RSA key is used):
297 openssl pkeyutl -verifyrecover -in sig -inkey key.pem
299 Verify the signature (e.g. a DSA key):
301 openssl pkeyutl -verify -in file -sigfile sig -inkey key.pem
303 Sign data using a message digest value (this is currently only valid for RSA):
305 openssl pkeyutl -sign -in file -inkey key.pem -out sig -pkeyopt digest:sha256
307 Derive a shared secret value:
309 openssl pkeyutl -derive -inkey key.pem -peerkey pubkey.pem -out secret
311 Hexdump 48 bytes of TLS1 PRF using digest B<SHA256> and shared secret and
312 seed consisting of the single byte 0xFF:
314 openssl pkeyutl -kdf TLS1-PRF -kdflen 48 -pkeyopt md:SHA256 \
315 -pkeyopt hexsecret:ff -pkeyopt hexseed:ff -hexdump
319 L<genpkey(1)>, L<pkey(1)>, L<rsautl(1)>
320 L<dgst(1)>, L<rsa(1)>, L<genrsa(1)>,
321 L<EVP_PKEY_CTX_set_hkdf_md(3)>, L<EVP_PKEY_CTX_set_tls1_prf_md(3)>
325 Copyright 2006-2017 The OpenSSL Project Authors. All Rights Reserved.
327 Licensed under the OpenSSL license (the "License"). You may not use
328 this file except in compliance with the License. You can obtain a copy
329 in the file LICENSE in the source distribution or at
330 L<https://www.openssl.org/source/license.html>.