dgst.pod revision 273149
1=pod 2 3=head1 NAME 4 5dgst, sha, sha1, mdc2, ripemd160, sha224, sha256, sha384, sha512, md2, md4, md5, dss1 - message digests 6 7=head1 SYNOPSIS 8 9B<openssl> B<dgst> 10[B<-sha|-sha1|-mdc2|-ripemd160|-sha224|-sha256|-sha384|-sha512|-md2|-md4|-md5|-dss1>] 11[B<-c>] 12[B<-d>] 13[B<-hex>] 14[B<-binary>] 15[B<-r>] 16[B<-out filename>] 17[B<-sign filename>] 18[B<-keyform arg>] 19[B<-passin arg>] 20[B<-verify filename>] 21[B<-prverify filename>] 22[B<-signature filename>] 23[B<-hmac key>] 24[B<-non-fips-allow>] 25[B<-fips-fingerprint>] 26[B<file...>] 27 28B<openssl> 29[I<digest>] 30[B<...>] 31 32=head1 DESCRIPTION 33 34The digest functions output the message digest of a supplied file or files 35in hexadecimal. The digest functions also generate and verify digital 36signatures using message digests. 37 38=head1 OPTIONS 39 40=over 4 41 42=item B<-c> 43 44print out the digest in two digit groups separated by colons, only relevant if 45B<hex> format output is used. 46 47=item B<-d> 48 49print out BIO debugging information. 50 51=item B<-hex> 52 53digest is to be output as a hex dump. This is the default case for a "normal" 54digest as opposed to a digital signature. See NOTES below for digital 55signatures using B<-hex>. 56 57=item B<-binary> 58 59output the digest or signature in binary form. 60 61=item B<-r> 62 63output the digest in the "coreutils" format used by programs like B<sha1sum>. 64 65=item B<-out filename> 66 67filename to output to, or standard output by default. 68 69=item B<-sign filename> 70 71digitally sign the digest using the private key in "filename". 72 73=item B<-keyform arg> 74 75Specifies the key format to sign digest with. The DER, PEM, P12, 76and ENGINE formats are supported. 77 78=item B<-engine id> 79 80Use engine B<id> for operations (including private key storage). 81This engine is not used as source for digest algorithms, unless it is 82also specified in the configuration file. 83 84=item B<-sigopt nm:v> 85 86Pass options to the signature algorithm during sign or verify operations. 87Names and values of these options are algorithm-specific. 88 89 90=item B<-passin arg> 91 92the private key password source. For more information about the format of B<arg> 93see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>. 94 95=item B<-verify filename> 96 97verify the signature using the public key in "filename". 98The output is either "Verification OK" or "Verification Failure". 99 100=item B<-prverify filename> 101 102verify the signature using the private key in "filename". 103 104=item B<-signature filename> 105 106the actual signature to verify. 107 108=item B<-hmac key> 109 110create a hashed MAC using "key". 111 112=item B<-mac alg> 113 114create MAC (keyed Message Authentication Code). The most popular MAC 115algorithm is HMAC (hash-based MAC), but there are other MAC algorithms 116which are not based on hash, for instance B<gost-mac> algorithm, 117supported by B<ccgost> engine. MAC keys and other options should be set 118via B<-macopt> parameter. 119 120=item B<-macopt nm:v> 121 122Passes options to MAC algorithm, specified by B<-mac> key. 123Following options are supported by both by B<HMAC> and B<gost-mac>: 124 125=over 8 126 127=item B<key:string> 128 129Specifies MAC key as alphnumeric string (use if key contain printable 130characters only). String length must conform to any restrictions of 131the MAC algorithm for example exactly 32 chars for gost-mac. 132 133=item B<hexkey:string> 134 135Specifies MAC key in hexadecimal form (two hex digits per byte). 136Key length must conform to any restrictions of the MAC algorithm 137for example exactly 32 chars for gost-mac. 138 139=back 140 141=item B<-rand file(s)> 142 143a file or files containing random data used to seed the random number 144generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>). 145Multiple files can be specified separated by a OS-dependent character. 146The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for 147all others. 148 149=item B<-non-fips-allow> 150 151enable use of non-FIPS algorithms such as MD5 even in FIPS mode. 152 153=item B<-fips-fingerprint> 154 155compute HMAC using a specific key 156for certain OpenSSL-FIPS operations. 157 158=item B<file...> 159 160file or files to digest. If no files are specified then standard input is 161used. 162 163=back 164 165 166=head1 EXAMPLES 167 168To create a hex-encoded message digest of a file: 169 openssl dgst -md5 -hex file.txt 170 171To sign a file using SHA-256 with binary file output: 172 openssl dgst -sha256 -sign privatekey.pem -out signature.sign file.txt 173 174To verify a signature: 175 openssl dgst -sha256 -verify publickey.pem \ 176 -signature signature.sign \ 177 file.txt 178 179 180=head1 NOTES 181 182The digest of choice for all new applications is SHA1. Other digests are 183however still widely used. 184 185When signing a file, B<dgst> will automatically determine the algorithm 186(RSA, ECC, etc) to use for signing based on the private key's ASN.1 info. 187When verifying signatures, it only handles the RSA, DSA, or ECDSA signature 188itself, not the related data to identify the signer and algorithm used in 189formats such as x.509, CMS, and S/MIME. 190 191A source of random numbers is required for certain signing algorithms, in 192particular ECDSA and DSA. 193 194The signing and verify options should only be used if a single file is 195being signed or verified. 196 197Hex signatures cannot be verified using B<openssl>. Instead, use "xxd -r" 198or similar program to transform the hex signature into a binary signature 199prior to verification. 200 201 202=cut 203