6 - perform digest operations
23 [B<-prverify filename>]
24 [B<-signature filename>]
26 [B<-fips-fingerprint>]
32 B<openssl> I<digest> [B<...>]
36 The digest functions output the message digest of a supplied file or files
37 in hexadecimal. The digest functions also generate and verify digital
38 signatures using message digests.
40 The generic name, B<dgst>, may be used with an option specifying the
42 The default digest is I<sha256>.
43 A supported I<digest> name may also be used as the command name.
44 To see the list of supported algorithms, use the I<list --digest-commands>
53 Print out a usage message.
57 Specifies name of a supported digest to be used. To see the list of
58 supported digests, use the command I<list --digest-commands>.
62 Print out the digest in two digit groups separated by colons, only relevant if
63 B<hex> format output is used.
67 Print out BIO debugging information.
71 Digest is to be output as a hex dump. This is the default case for a "normal"
72 digest as opposed to a digital signature. See NOTES below for digital
73 signatures using B<-hex>.
77 Output the digest or signature in binary form.
81 Output the digest in the "coreutils" format used by programs like B<sha1sum>.
83 =item B<-out filename>
85 Filename to output to, or standard output by default.
87 =item B<-sign filename>
89 Digitally sign the digest using the private key in "filename".
93 Specifies the key format to sign digest with. The DER, PEM, P12,
94 and ENGINE formats are supported.
98 Pass options to the signature algorithm during sign or verify operations.
99 Names and values of these options are algorithm-specific.
103 The private key password source. For more information about the format of B<arg>
104 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
106 =item B<-verify filename>
108 Verify the signature using the public key in "filename".
109 The output is either "Verification OK" or "Verification Failure".
111 =item B<-prverify filename>
113 Verify the signature using the private key in "filename".
115 =item B<-signature filename>
117 The actual signature to verify.
121 Create a hashed MAC using "key".
125 Create MAC (keyed Message Authentication Code). The most popular MAC
126 algorithm is HMAC (hash-based MAC), but there are other MAC algorithms
127 which are not based on hash, for instance B<gost-mac> algorithm,
128 supported by B<ccgost> engine. MAC keys and other options should be set
129 via B<-macopt> parameter.
131 =item B<-macopt nm:v>
133 Passes options to MAC algorithm, specified by B<-mac> key.
134 Following options are supported by both by B<HMAC> and B<gost-mac>:
140 Specifies MAC key as alphanumeric string (use if key contain printable
141 characters only). String length must conform to any restrictions of
142 the MAC algorithm for example exactly 32 chars for gost-mac.
144 =item B<hexkey:string>
146 Specifies MAC key in hexadecimal form (two hex digits per byte).
147 Key length must conform to any restrictions of the MAC algorithm
148 for example exactly 32 chars for gost-mac.
152 =item B<-rand file...>
154 A file or files containing random data used to seed the random number
156 Multiple files can be specified separated by an OS-dependent character.
157 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
160 =item [B<-writerand file>]
162 Writes random data to the specified I<file> upon exit.
163 This can be used with a subsequent B<-rand> flag.
165 =item B<-fips-fingerprint>
167 Compute HMAC using a specific key for certain OpenSSL-FIPS operations.
171 Use engine B<id> for operations (including private key storage).
172 This engine is not used as source for digest algorithms, unless it is
173 also specified in the configuration file or B<-engine_impl> is also
176 =item B<-engine_impl>
178 When used with the B<-engine> option, it specifies to also use
179 engine B<id> for digest operations.
183 File or files to digest. If no files are specified then standard input is
191 To create a hex-encoded message digest of a file:
192 openssl dgst -md5 -hex file.txt
194 To sign a file using SHA-256 with binary file output:
195 openssl dgst -sha256 -sign privatekey.pem -out signature.sign file.txt
197 To verify a signature:
198 openssl dgst -sha256 -verify publickey.pem \
199 -signature signature.sign \
205 The digest mechanisms that are available will depend on the options
206 used when building OpenSSL.
207 The B<list digest-commands> command can be used to list them.
209 New or agile applications should use probably use SHA-256. Other digests,
210 particularly SHA-1 and MD5, are still widely used for interoperating
211 with existing formats and protocols.
213 When signing a file, B<dgst> will automatically determine the algorithm
214 (RSA, ECC, etc) to use for signing based on the private key's ASN.1 info.
215 When verifying signatures, it only handles the RSA, DSA, or ECDSA signature
216 itself, not the related data to identify the signer and algorithm used in
217 formats such as x.509, CMS, and S/MIME.
219 A source of random numbers is required for certain signing algorithms, in
220 particular ECDSA and DSA.
222 The signing and verify options should only be used if a single file is
223 being signed or verified.
225 Hex signatures cannot be verified using B<openssl>. Instead, use "xxd -r"
226 or similar program to transform the hex signature into a binary signature
227 prior to verification.
231 The default digest was changed from MD5 to SHA256 in OpenSSL 1.1.0
232 The FIPS-related options were removed in OpenSSL 1.1.0
236 Copyright 2000-2017 The OpenSSL Project Authors. All Rights Reserved.
238 Licensed under the OpenSSL license (the "License"). You may not use
239 this file except in compliance with the License. You can obtain a copy
240 in the file LICENSE in the source distribution or at
241 L<https://www.openssl.org/source/license.html>.