dgst.pod revision 279264 
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<-hmac arg>]
17[B<-non-fips-allow>]
18[B<-out filename>]
19[B<-sign filename>]
20[B<-keyform arg>]
21[B<-passin arg>]
22[B<-verify filename>]
23[B<-prverify filename>]
24[B<-signature filename>]
25[B<-hmac key>]
26[B<-non-fips-allow>]
27[B<-fips-fingerprint>]
28[B<file...>]
29
30B<openssl>
31[I<digest>]
32[B<...>]
33
34=head1 DESCRIPTION
35
36The digest functions output the message digest of a supplied file or files
37in hexadecimal.  The digest functions also generate and verify digital
38signatures using message digests.
39
40=head1 OPTIONS
41
42=over 4
43
44=item B<-c>
45
46print out the digest in two digit groups separated by colons, only relevant if
47B<hex> format output is used.
48
49=item B<-d>
50
51print out BIO debugging information.
52
53=item B<-hex>
54
55digest is to be output as a hex dump. This is the default case for a "normal"
56digest as opposed to a digital signature.  See NOTES below for digital
57signatures using B<-hex>.
58
59=item B<-binary>
60
61output the digest or signature in binary form.
62
63=item B<-r>
64
65output the digest in the "coreutils" format used by programs like B<sha1sum>.
66
67=item B<-hmac arg>
68
69set the HMAC key to "arg".
70
71=item B<-non-fips-allow>
72
73Allow use of non FIPS digest when in FIPS mode.  This has no effect when not in
74FIPS mode.
75
76=item B<-out filename>
77
78filename to output to, or standard output by default.
79
80=item B<-sign filename>
81
82digitally sign the digest using the private key in "filename".
83
84=item B<-keyform arg>
85
86Specifies the key format to sign digest with. The DER, PEM, P12,
87and ENGINE formats are supported.
88
89=item B<-engine id>
90
91Use engine B<id> for operations (including private key storage).
92This engine is not used as source for digest algorithms, unless it is
93also specified in the configuration file.
94
95=item B<-sigopt nm:v>
96
97Pass options to the signature algorithm during sign or verify operations.
98Names and values of these options are algorithm-specific.
99
100
101=item B<-passin arg>
102
103the private key password source. For more information about the format of B<arg>
104see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
105
106=item B<-verify filename>
107
108verify the signature using the public key in "filename".
109The output is either "Verification OK" or "Verification Failure".
110
111=item B<-prverify filename>
112
113verify the signature using the private key in "filename".
114
115=item B<-signature filename>
116
117the actual signature to verify.
118
119=item B<-hmac key>
120
121create a hashed MAC using "key".
122
123=item B<-mac alg>
124
125create MAC (keyed Message Authentication Code). The most popular MAC
126algorithm is HMAC (hash-based MAC), but there are other MAC algorithms
127which are not based on hash, for instance B<gost-mac> algorithm,
128supported by B<ccgost> engine. MAC keys and other options should be set
129via B<-macopt> parameter.
130
131=item B<-macopt nm:v>
132
133Passes options to MAC algorithm, specified by B<-mac> key.
134Following options are supported by both by B<HMAC> and B<gost-mac>:
135
136=over 8
137
138=item B<key:string>
139
140Specifies MAC key as alphnumeric string (use if key contain printable
141characters only). String length must conform to any restrictions of
142the MAC algorithm for example exactly 32 chars for gost-mac.
143
144=item B<hexkey:string>
145
146Specifies MAC key in hexadecimal form (two hex digits per byte).
147Key length must conform to any restrictions of the MAC algorithm
148for example exactly 32 chars for gost-mac.
149
150=back
151
152=item B<-rand file(s)>
153
154a file or files containing random data used to seed the random number
155generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
156Multiple files can be specified separated by a OS-dependent character.
157The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
158all others. 
159
160=item B<-non-fips-allow>
161
162enable use of non-FIPS algorithms such as MD5 even in FIPS mode.
163
164=item B<-fips-fingerprint>
165
166compute HMAC using a specific key
167for certain OpenSSL-FIPS operations.
168
169=item B<file...>
170
171file or files to digest. If no files are specified then standard input is
172used.
173
174=back
175
176
177=head1 EXAMPLES
178
179To create a hex-encoded message digest of a file:
180 openssl dgst -md5 -hex file.txt
181
182To sign a file using SHA-256 with binary file output:
183 openssl dgst -sha256 -sign privatekey.pem -out signature.sign file.txt
184
185To verify a signature:
186 openssl dgst -sha256 -verify publickey.pem \
187 -signature signature.sign \
188 file.txt
189
190
191=head1 NOTES
192
193The digest of choice for all new applications is SHA1. Other digests are
194however still widely used.
195
196When signing a file, B<dgst> will automatically determine the algorithm
197(RSA, ECC, etc) to use for signing based on the private key's ASN.1 info.
198When verifying signatures, it only handles the RSA, DSA, or ECDSA signature
199itself, not the related data to identify the signer and algorithm used in
200formats such as x.509, CMS, and S/MIME.
201
202A source of random numbers is required for certain signing algorithms, in
203particular ECDSA and DSA.
204
205The signing and verify options should only be used if a single file is
206being signed or verified.
207
208Hex signatures cannot be verified using B<openssl>.  Instead, use "xxd -r"
209or similar program to transform the hex signature into a binary signature
210prior to verification.
211
212
213=cut
214