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