1=pod 2 3=head1 NAME 4 5pkeyutl - public key algorithm utility 6 7=head1 SYNOPSIS 8 9B<openssl> B<pkeyutl> 10[B<-in file>] 11[B<-out file>] 12[B<-sigfile file>] 13[B<-inkey file>] 14[B<-keyform PEM|DER>] 15[B<-passin arg>] 16[B<-peerkey file>] 17[B<-peerform PEM|DER>] 18[B<-pubin>] 19[B<-certin>] 20[B<-rev>] 21[B<-sign>] 22[B<-verify>] 23[B<-verifyrecover>] 24[B<-encrypt>] 25[B<-decrypt>] 26[B<-derive>] 27[B<-pkeyopt opt:value>] 28[B<-hexdump>] 29[B<-asn1parse>] 30[B<-engine id>] 31 32=head1 DESCRIPTION 33 34The B<pkeyutl> command can be used to perform public key operations using 35any supported algorithm. 36 37=head1 COMMAND OPTIONS 38 39=over 4 40 41=item B<-in filename> 42 43This specifies the input filename to read data from or standard input 44if this option is not specified. 45 46=item B<-out filename> 47 48specifies the output filename to write to or standard output by 49default. 50 51=item B<-inkey file> 52 53the input key file, by default it should be a private key. 54 55=item B<-keyform PEM|DER> 56 57the key format PEM, DER or ENGINE. 58 59=item B<-passin arg> 60 61the input key password source. For more information about the format of B<arg> 62see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>. 63 64 65=item B<-peerkey file> 66 67the peer key file, used by key derivation (agreement) operations. 68 69=item B<-peerform PEM|DER> 70 71the peer key format PEM, DER or ENGINE. 72 73=item B<-engine id> 74 75specifying an engine (by its unique B<id> string) will cause B<pkeyutl> 76to attempt to obtain a functional reference to the specified engine, 77thus initialising it if needed. The engine will then be set as the default 78for all available algorithms. 79 80 81=item B<-pubin> 82 83the input file is a public key. 84 85=item B<-certin> 86 87the input is a certificate containing a public key. 88 89=item B<-rev> 90 91reverse the order of the input buffer. This is useful for some libraries 92(such as CryptoAPI) which represent the buffer in little endian format. 93 94=item B<-sign> 95 96sign the input data and output the signed result. This requires 97a private key. 98 99=item B<-verify> 100 101verify the input data against the signature file and indicate if the 102verification succeeded or failed. 103 104=item B<-verifyrecover> 105 106verify the input data and output the recovered data. 107 108=item B<-encrypt> 109 110encrypt the input data using a public key. 111 112=item B<-decrypt> 113 114decrypt the input data using a private key. 115 116=item B<-derive> 117 118derive a shared secret using the peer key. 119 120=item B<-hexdump> 121 122hex dump the output data. 123 124=item B<-asn1parse> 125 126asn1parse the output data, this is useful when combined with the 127B<-verifyrecover> option when an ASN1 structure is signed. 128 129=back 130 131=head1 NOTES 132 133The operations and options supported vary according to the key algorithm 134and its implementation. The OpenSSL operations and options are indicated below. 135 136Unless otherwise mentioned all algorithms support the B<digest:alg> option 137which specifies the digest in use for sign, verify and verifyrecover operations. 138The value B<alg> should represent a digest name as used in the 139EVP_get_digestbyname() function for example B<sha1>. 140This value is used only for sanity-checking the lengths of data passed in to 141the B<pkeyutl> and for creating the structures that make up the signature 142(e.g. B<DigestInfo> in RSASSA PKCS#1 v1.5 signatures). 143In case of RSA, ECDSA and DSA signatures, this utility 144will not perform hashing on input data but rather use the data directly as 145input of signature algorithm. Depending on key type, signature type and mode 146of padding, the maximum acceptable lengths of input data differ. In general, 147with RSA the signed data can't be longer than the key modulus, in case of ECDSA 148and DSA the data shouldn't be longer than field size, otherwise it will be 149silently truncated to field size. 150 151In other words, if the value of digest is B<sha1> the input should be 20 bytes 152long binary encoding of SHA-1 hash function output. 153 154=head1 RSA ALGORITHM 155 156The RSA algorithm supports encrypt, decrypt, sign, verify and verifyrecover 157operations in general. Some padding modes only support some of these 158operations however. 159 160=over 4 161 162=item -B<rsa_padding_mode:mode> 163 164This sets the RSA padding mode. Acceptable values for B<mode> are B<pkcs1> for 165PKCS#1 padding, B<sslv23> for SSLv23 padding, B<none> for no padding, B<oaep> 166for B<OAEP> mode, B<x931> for X9.31 mode and B<pss> for PSS. 167 168In PKCS#1 padding if the message digest is not set then the supplied data is 169signed or verified directly instead of using a B<DigestInfo> structure. If a 170digest is set then the a B<DigestInfo> structure is used and its the length 171must correspond to the digest type. 172 173For B<oeap> mode only encryption and decryption is supported. 174 175For B<x931> if the digest type is set it is used to format the block data 176otherwise the first byte is used to specify the X9.31 digest ID. Sign, 177verify and verifyrecover are can be performed in this mode. 178 179For B<pss> mode only sign and verify are supported and the digest type must be 180specified. 181 182=item B<rsa_pss_saltlen:len> 183 184For B<pss> mode only this option specifies the salt length. Two special values 185are supported: -1 sets the salt length to the digest length. When signing -2 186sets the salt length to the maximum permissible value. When verifying -2 causes 187the salt length to be automatically determined based on the B<PSS> block 188structure. 189 190=back 191 192=head1 DSA ALGORITHM 193 194The DSA algorithm supports signing and verification operations only. Currently 195there are no additional options other than B<digest>. Only the SHA1 196digest can be used and this digest is assumed by default. 197 198=head1 DH ALGORITHM 199 200The DH algorithm only supports the derivation operation and no additional 201options. 202 203=head1 EC ALGORITHM 204 205The EC algorithm supports sign, verify and derive operations. The sign and 206verify operations use ECDSA and derive uses ECDH. Currently there are no 207additional options other than B<digest>. Only the SHA1 digest can be used and 208this digest is assumed by default. 209 210=head1 EXAMPLES 211 212Sign some data using a private key: 213 214 openssl pkeyutl -sign -in file -inkey key.pem -out sig 215 216Recover the signed data (e.g. if an RSA key is used): 217 218 openssl pkeyutl -verifyrecover -in sig -inkey key.pem 219 220Verify the signature (e.g. a DSA key): 221 222 openssl pkeyutl -verify -in file -sigfile sig -inkey key.pem 223 224Sign data using a message digest value (this is currently only valid for RSA): 225 226 openssl pkeyutl -sign -in file -inkey key.pem -out sig -pkeyopt digest:sha256 227 228Derive a shared secret value: 229 230 openssl pkeyutl -derive -inkey key.pem -peerkey pubkey.pem -out secret 231 232=head1 SEE ALSO 233 234L<genpkey(1)|genpkey(1)>, L<pkey(1)|pkey(1)>, L<rsautl(1)|rsautl(1)> 235L<dgst(1)|dgst(1)>, L<rsa(1)|rsa(1)>, L<genrsa(1)|genrsa(1)> 236