=head1 NAME
-dgst, md5, md4, md2, sha1, sha, mdc2, ripemd160 - message digests
+dgst, sha, sha1, mdc2, ripemd160, sha224, sha256, sha384, sha512, md4, md5 - message digests
=head1 SYNOPSIS
B<openssl> B<dgst>
-[B<-md5|-md4|-md2|-sha1|-sha|-mdc2|-ripemd160|-dss1>]
+[B<-sha|-sha1|-mdc2|-ripemd160|-sha224|-sha256|-sha384|-sha512|-md4|-md5>]
[B<-c>]
[B<-d>]
[B<-hex>]
[B<-binary>]
+[B<-r>]
[B<-out filename>]
[B<-sign filename>]
+[B<-keyform arg>]
+[B<-passin arg>]
[B<-verify filename>]
[B<-prverify filename>]
[B<-signature filename>]
+[B<-hmac key>]
+[B<-fips-fingerprint>]
[B<file...>]
-[B<md5|md4|md2|sha1|sha|mdc2|ripemd160>]
-[B<-c>]
-[B<-d>]
-[B<file...>]
+B<openssl>
+[I<digest>]
+[B<...>]
=head1 DESCRIPTION
The digest functions output the message digest of a supplied file or files
-in hexadecimal form. They can also be used for digital signing and verification.
+in hexadecimal. The digest functions also generate and verify digital
+signatures using message digests.
+
+The generic name, B<dgst>, may be used with an option specifying the
+algorithm to be used.
+The default digest is I<sha256>.
+The digest name may also be used as the command name.
+To see the list of supported algorithms, use the <Ilist --digest-commands>
+command.
=head1 OPTIONS
=item B<-hex>
digest is to be output as a hex dump. This is the default case for a "normal"
-digest as opposed to a digital signature.
+digest as opposed to a digital signature. See NOTES below for digital
+signatures using B<-hex>.
=item B<-binary>
output the digest or signature in binary form.
+=item B<-r>
+
+output the digest in the "coreutils" format used by programs like B<sha1sum>.
+
=item B<-out filename>
filename to output to, or standard output by default.
digitally sign the digest using the private key in "filename".
+=item B<-keyform arg>
+
+Specifies the key format to sign digest with. The DER, PEM, P12,
+and ENGINE formats are supported.
+
+=item B<-engine id>
+
+Use engine B<id> for operations (including private key storage).
+This engine is not used as source for digest algorithms, unless it is
+also specified in the configuration file.
+
+=item B<-sigopt nm:v>
+
+Pass options to the signature algorithm during sign or verify operations.
+Names and values of these options are algorithm-specific.
+
+
+=item B<-passin arg>
+
+the private key password source. For more information about the format of B<arg>
+see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
+
=item B<-verify filename>
verify the signature using the the public key in "filename".
the actual signature to verify.
+=item B<-hmac key>
+
+create a hashed MAC using "key".
+
+=item B<-mac alg>
+
+create MAC (keyed Message Authentication Code). The most popular MAC
+algorithm is HMAC (hash-based MAC), but there are other MAC algorithms
+which are not based on hash, for instance B<gost-mac> algorithm,
+supported by B<ccgost> engine. MAC keys and other options should be set
+via B<-macopt> parameter.
+
+=item B<-macopt nm:v>
+
+Passes options to MAC algorithm, specified by B<-mac> key.
+Following options are supported by both by B<HMAC> and B<gost-mac>:
+
+=over 8
+
+=item B<key:string>
+
+Specifies MAC key as alphanumeric string (use if key contain printable
+characters only). String length must conform to any restrictions of
+the MAC algorithm for example exactly 32 chars for gost-mac.
+
+=item B<hexkey:string>
+
+Specifies MAC key in hexadecimal form (two hex digits per byte).
+Key length must conform to any restrictions of the MAC algorithm
+for example exactly 32 chars for gost-mac.
+
+=back
+
=item B<-rand file(s)>
a file or files containing random data used to seed the random number
-generator, or an EGD socket (see L<RAND_egd(3)|RAND_egd(3)>).
+generator, or an EGD socket (see L<RAND_egd(3)>).
Multiple files can be specified separated by a OS-dependent character.
The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
all others.
+=item B<-fips-fingerprint>
+
+compute HMAC using a specific key
+for certain OpenSSL-FIPS operations.
+
=item B<file...>
file or files to digest. If no files are specified then standard input is
=back
+
+=head1 EXAMPLES
+
+To create a hex-encoded message digest of a file:
+ openssl dgst -md5 -hex file.txt
+
+To sign a file using SHA-256 with binary file output:
+ openssl dgst -sha256 -sign privatekey.pem -out signature.sign file.txt
+
+To verify a signature:
+ openssl dgst -sha256 -verify publickey.pem \
+ -signature signature.sign \
+ file.txt
+
+
=head1 NOTES
-The digest of choice for all new applications is SHA1. Other digests are
-however still widely used.
+The digest mechanisms that are available will depend on the options
+used when building OpenSSL.
+The B<list digest-commands> command can be used to list them.
+
+New or agile applications should use probably use SHA-256. Other digests,
+particularly SHA-1 and MD5, are still widely used for interoperating
+with existing formats and protocols.
-If you wish to sign or verify data using the DSA algorithm then the dss1
-digest must be used.
+When signing a file, B<dgst> will automatically determine the algorithm
+(RSA, ECC, etc) to use for signing based on the private key's ASN.1 info.
+When verifying signatures, it only handles the RSA, DSA, or ECDSA signature
+itself, not the related data to identify the signer and algorithm used in
+formats such as x.509, CMS, and S/MIME.
A source of random numbers is required for certain signing algorithms, in
-particular DSA.
+particular ECDSA and DSA.
The signing and verify options should only be used if a single file is
being signed or verified.
+Hex signatures cannot be verified using B<openssl>. Instead, use "xxd -r"
+or similar program to transform the hex signature into a binary signature
+prior to verification.
+
+=head1 HISTORY
+
+The default digest was changed from MD5 to SHA256 in Openssl 1.1.
+The FIPS-related options were removed in OpenSSL 1.1
+
=cut
projects / openssl.git / blobdiff