doc/man1/openssl-dgst.pod

   1 =pod
   2
   3 =head1 NAME
   4
   5 openssl-dgst - perform digest operations
   6
   7 =head1 SYNOPSIS
   8
   9 B<openssl> B<dgst>|I<digest>
  10 [B<-I<digest>>]
  11 [B<-help>]
  12 [B<-c>]
  13 [B<-d>]
  14 [B<-list>]
  15 [B<-hex>]
  16 [B<-binary>]
  17 [B<-r>]
  18 [B<-out> I<filename>]
  19 [B<-sign> I<filename>]
  20 [B<-keyform> I<arg>]
  21 [B<-passin> I<arg>]
  22 [B<-verify> I<filename>]
  23 [B<-prverify> I<filename>]
  24 [B<-signature> I<filename>]
  25 [B<-sigopt> I<nm>:I<v>]
  26 [B<-hmac> I<key>]
  27 [B<-fips-fingerprint>]
  28 [B<-rand> I<files>]
  29 [B<-writerand> I<file>]
  30 [B<-engine> I<id>]
  31 [B<-engine_impl>]
  32 [I<file> ...]
  33
  34 =head1 DESCRIPTION
  35
  36 This command output the message digest of a supplied file or files
  37 in hexadecimal, and also generates and verifies digital
  38 signatures using message digests.
  39
  40 The generic name, B<openssl dgst>, may be used with an option specifying the
  41 algorithm to be used.
  42 The default digest is B<sha256>.
  43 A supported I<digest> name may also be used as the sub-command name.
  44 To see the list of supported algorithms, use C<openssl list -digest-commands>
  45
  46 =head1 OPTIONS
  47
  48 =over 4
  49
  50 =item B<-help>
  51
  52 Print out a usage message.
  53
  54 =item B<-I<digest>>
  55
  56 Specifies name of a supported digest to be used. To see the list of
  57 supported digests, use the command C<list --digest-commands>.
  58
  59 =item B<-c>
  60
  61 Print out the digest in two digit groups separated by colons, only relevant if
  62 the B<-hex> option is given as well.
  63
  64 =item B<-d>
  65
  66 Print out BIO debugging information.
  67
  68 =item B<-list>
  69
  70 Prints out a list of supported message digests.
  71
  72 =item B<-hex>
  73
  74 Digest is to be output as a hex dump. This is the default case for a "normal"
  75 digest as opposed to a digital signature.  See NOTES below for digital
  76 signatures using B<-hex>.
  77
  78 =item B<-binary>
  79
  80 Output the digest or signature in binary form.
  81
  82 =item B<-r>
  83
  84 Output the digest in the "coreutils" format, including newlines.
  85 Used by programs like L<sha1sum(1)>.
  86
  87 =item B<-out> I<filename>
  88
  89 Filename to output to, or standard output by default.
  90
  91 =item B<-sign> I<filename>
  92
  93 Digitally sign the digest using the private key in "filename". Note this option
  94 does not support Ed25519 or Ed448 private keys. Use the L<openssl-pkeyutl(1)>
  95 command instead for this.
  96
  97 =item B<-keyform> I<arg>
  98
  99 Specifies the key format to sign digest with. The DER, PEM, P12,
 100 and ENGINE formats are supported.
 101
 102 =item B<-sigopt> I<nm>:I<v>
 103
 104 Pass options to the signature algorithm during sign or verify operations.
 105 Names and values of these options are algorithm-specific.
 106
 107 =item B<-passin> I<arg>
 108
 109 The private key password source. For more information about the format of I<arg>
 110 see L<openssl(1)/Pass Phrase Options>.
 111
 112 =item B<-verify> I<filename>
 113
 114 Verify the signature using the public key in "filename".
 115 The output is either "Verification OK" or "Verification Failure".
 116
 117 =item B<-prverify> I<filename>
 118
 119 Verify the signature using the private key in "filename".
 120
 121 =item B<-signature> I<filename>
 122
 123 The actual signature to verify.
 124
 125 =item B<-hmac> I<key>
 126
 127 Create a hashed MAC using "key".
 128
 129 The L<openssl-mac(1)> command should be preferred to using this command line
 130 option.
 131
 132 =item B<-mac> I<alg>
 133
 134 Create MAC (keyed Message Authentication Code). The most popular MAC
 135 algorithm is HMAC (hash-based MAC), but there are other MAC algorithms
 136 which are not based on hash, for instance B<gost-mac> algorithm,
 137 supported by the B<gost> engine. MAC keys and other options should be set
 138 via B<-macopt> parameter.
 139
 140 The L<openssl-mac(1)> command should be preferred to using this command line
 141 option.
 142
 143 =item B<-macopt> I<nm>:I<v>
 144
 145 Passes options to MAC algorithm, specified by B<-mac> key.
 146 Following options are supported by both by B<HMAC> and B<gost-mac>:
 147
 148 =over 4
 149
 150 =item B<key>:I<string>
 151
 152 Specifies MAC key as alphanumeric string (use if key contain printable
 153 characters only). String length must conform to any restrictions of
 154 the MAC algorithm for example exactly 32 chars for gost-mac.
 155
 156 =item B<hexkey>:I<string>
 157
 158 Specifies MAC key in hexadecimal form (two hex digits per byte).
 159 Key length must conform to any restrictions of the MAC algorithm
 160 for example exactly 32 chars for gost-mac.
 161
 162 =back
 163
 164 The L<openssl-mac(1)> command should be preferred to using this command line
 165 option.
 166
 167 =item B<-rand> I<files>, B<-writerand> I<file>
 168
 169 See L<openssl(1)/Random State Options> for more information.
 170
 171 =item B<-fips-fingerprint>
 172
 173 Compute HMAC using a specific key for certain OpenSSL-FIPS operations.
 174
 175 =item B<-engine> I<id>
 176
 177 Use engine I<id> for operations (including private key storage).
 178 This engine is not used as source for digest algorithms, unless it is
 179 also specified in the configuration file or B<-engine_impl> is also
 180 specified.
 181
 182 =item B<-engine_impl>
 183
 184 When used with the B<-engine> option, it specifies to also use
 185 engine I<id> for digest operations.
 186
 187 =item I<file> ...
 188
 189 File or files to digest. If no files are specified then standard input is
 190 used.
 191
 192 =back
 193
 194
 195 =head1 EXAMPLES
 196
 197 To create a hex-encoded message digest of a file:
 198  openssl dgst -md5 -hex file.txt
 199
 200 To sign a file using SHA-256 with binary file output:
 201  openssl dgst -sha256 -sign privatekey.pem -out signature.sign file.txt
 202
 203 To verify a signature:
 204  openssl dgst -sha256 -verify publickey.pem \
 205  -signature signature.sign \
 206  file.txt
 207
 208
 209 =head1 NOTES
 210
 211 The digest mechanisms that are available will depend on the options
 212 used when building OpenSSL.
 213 The C<openssl list -digest-commands> command can be used to list them.
 214
 215 New or agile applications should use probably use SHA-256. Other digests,
 216 particularly SHA-1 and MD5, are still widely used for interoperating
 217 with existing formats and protocols.
 218
 219 When signing a file, this command will automatically determine the algorithm
 220 (RSA, ECC, etc) to use for signing based on the private key's ASN.1 info.
 221 When verifying signatures, it only handles the RSA, DSA, or ECDSA signature
 222 itself, not the related data to identify the signer and algorithm used in
 223 formats such as x.509, CMS, and S/MIME.
 224
 225 A source of random numbers is required for certain signing algorithms, in
 226 particular ECDSA and DSA.
 227
 228 The signing and verify options should only be used if a single file is
 229 being signed or verified.
 230
 231 Hex signatures cannot be verified using B<openssl>.  Instead, use "xxd -r"
 232 or similar program to transform the hex signature into a binary signature
 233 prior to verification.
 234
 235 The L<openssl-mac(1)> command is preferred over the B<-hmac>, B<-mac> and
 236 B<-macopt> command line options.
 237
 238 =head1 SEE ALSO
 239
 240 L<openssl-mac(1)>
 241
 242 =head1 HISTORY
 243
 244 The default digest was changed from MD5 to SHA256 in OpenSSL 1.1.0.
 245 The FIPS-related options were removed in OpenSSL 1.1.0.
 246
 247 =head1 COPYRIGHT
 248
 249 Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.
 250
 251 Licensed under the Apache License 2.0 (the "License").  You may not use
 252 this file except in compliance with the License.  You can obtain a copy
 253 in the file LICENSE in the source distribution or at
 254 L<https://www.openssl.org/source/license.html>.
 255
 256 =cut