5 pkeyutl - public key algorithm utility
17 [B<-peerform PEM|DER>]
27 [B<-pkeyopt opt:value>]
34 The B<pkeyutl> command can be used to perform public key operations using
35 any supported algorithm.
37 =head1 COMMAND OPTIONS
43 This specifies the input filename to read data from or standard input
44 if this option is not specified.
46 =item B<-out filename>
48 specifies the output filename to write to or standard output by
53 the input key file, by default it should be a private key.
55 =item B<-keyform PEM|DER>
57 the key format PEM, DER or ENGINE.
61 the input key password source. For more information about the format of B<arg>
62 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
65 =item B<-peerkey file>
67 the peer key file, used by key derivation (agreement) operations.
69 =item B<-peerform PEM|DER>
71 the peer key format PEM, DER or ENGINE.
75 specifying an engine (by its unique B<id> string) will cause B<pkeyutl>
76 to attempt to obtain a functional reference to the specified engine,
77 thus initialising it if needed. The engine will then be set as the default
78 for all available algorithms.
83 the input file is a public key.
87 the input is a certificate containing a public key.
91 reverse the order of the input buffer. This is useful for some libraries
92 (such as CryptoAPI) which represent the buffer in little endian format.
96 sign the input data and output the signed result. This requires
101 verify the input data against the signature file and indicate if the
102 verification succeeded or failed.
104 =item B<-verifyrecover>
106 verify the input data and output the recovered data.
110 encrypt the input data using a public key.
114 decrypt the input data using a private key.
118 derive a shared secret using the peer key.
122 hex dump the output data.
126 asn1parse the output data, this is useful when combined with the
127 B<-verifyrecover> option when an ASN1 structure is signed.
133 The operations and options supported vary according to the key algorithm
134 and its implementation. The OpenSSL operations and options are indicated below.
136 Unless otherwise mentioned all algorithms support the B<digest:alg> option
137 which specifies the digest in use for sign, verify and verifyrecover operations.
138 The value B<alg> should represent a digest name as used in the
139 EVP_get_digestbyname() function for example B<sha1>.
143 The RSA algorithm generally supports the encrypt, decrypt, sign,
144 verify and verifyrecover operations. However, some padding modes
145 support only a subset of these operations. The following additional
146 B<pkeyopt> values are supported:
150 =item B<rsa_padding_mode:mode>
152 This sets the RSA padding mode. Acceptable values for B<mode> are B<pkcs1> for
153 PKCS#1 padding, B<sslv23> for SSLv23 padding, B<none> for no padding, B<oaep>
154 for B<OAEP> mode, B<x931> for X9.31 mode and B<pss> for PSS.
156 In PKCS#1 padding if the message digest is not set then the supplied data is
157 signed or verified directly instead of using a B<DigestInfo> structure. If a
158 digest is set then the a B<DigestInfo> structure is used and its the length
159 must correspond to the digest type.
161 For B<oaep> mode only encryption and decryption is supported.
163 For B<x931> if the digest type is set it is used to format the block data
164 otherwise the first byte is used to specify the X9.31 digest ID. Sign,
165 verify and verifyrecover are can be performed in this mode.
167 For B<pss> mode only sign and verify are supported and the digest type must be
170 =item B<rsa_pss_saltlen:len>
172 For B<pss> mode only this option specifies the salt length. Two special values
173 are supported: -1 sets the salt length to the digest length. When signing -2
174 sets the salt length to the maximum permissible value. When verifying -2 causes
175 the salt length to be automatically determined based on the B<PSS> block
182 The DSA algorithm supports signing and verification operations only. Currently
183 there are no additional options other than B<digest>. Only the SHA1
184 digest can be used and this digest is assumed by default.
188 The DH algorithm only supports the derivation operation and no additional
193 The EC algorithm supports sign, verify and derive operations. The sign and
194 verify operations use ECDSA and derive uses ECDH. Currently there are no
195 additional options other than B<digest>. Only the SHA1 digest can be used and
196 this digest is assumed by default.
200 Sign some data using a private key:
202 openssl pkeyutl -sign -in file -inkey key.pem -out sig
204 Recover the signed data (e.g. if an RSA key is used):
206 openssl pkeyutl -verifyrecover -in sig -inkey key.pem
208 Verify the signature (e.g. a DSA key):
210 openssl pkeyutl -verify -in file -sigfile sig -inkey key.pem
212 Sign data using a message digest value (this is currently only valid for RSA):
214 openssl pkeyutl -sign -in file -inkey key.pem -out sig -pkeyopt digest:sha256
216 Derive a shared secret value:
218 openssl pkeyutl -derive -inkey key.pem -peerkey pubkey.pem -out secret
222 L<genpkey(1)>, L<pkey(1)>, L<rsautl(1)>
223 L<dgst(1)>, L<rsa(1)>, L<genrsa(1)>