NAME

       openssl-dgst, dgst - perform digest operations

SYNOPSIS

       openssl dgst [-digest] [-help] [-c] [-d] [-list] [-hex] [-binary] [-r] [-out filename] [-sign filename]
       [-keyform arg] [-passin arg] [-verify filename] [-prverify filename] [-signature filename] [-sigopt nm:v]
       [-hmac key] [-fips-fingerprint] [-rand file...]  [-engine id] [-engine_impl] [file...]

       openssl digest [...]

DESCRIPTION

       The digest functions output the message digest of a supplied file or files in hexadecimal.  The digest
       functions also generate and verify digital signatures using message digests.

       The generic name, dgst, may be used with an option specifying the algorithm to be used.  The default
       digest is sha256.  A supported digest name may also be used as the command name.  To see the list of
       supported algorithms, use the list --digest-commands command.

OPTIONS

       -help
           Print out a usage message.

       -digest
           Specifies name of a supported digest to be used. To see the list of supported digests, use the
           command list --digest-commands.

       -c  Print out the digest in two digit groups separated by colons, only relevant if hex format output is
           used.

       -d  Print out BIO debugging information.

       -list
           Prints out a list of supported message digests.

       -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.  See NOTES below for digital signatures using -hex.

       -binary
           Output the digest or signature in binary form.

       -r  Output the digest in the "coreutils" format, including newlines.  Used by programs like sha1sum.

       -out filename
           Filename to output to, or standard output by default.

       -sign filename
           Digitally sign the digest using the private key in "filename". Note this option does not support
           Ed25519 or Ed448 private keys. Use the pkeyutl command instead for this.

       -keyform arg
           Specifies the key format to sign digest with. The DER, PEM, P12, and ENGINE formats are supported.

       -sigopt nm:v
           Pass options to the signature algorithm during sign or verify operations.  Names and values of these
           options are algorithm-specific.

       -passin arg
           The private key password source. For more information about the format of arg see the PASS PHRASE
           ARGUMENTS section in openssl(1).

       -verify filename
           Verify the signature using the public key in "filename".  The output is either "Verification OK" or
           "Verification Failure".

       -prverify filename
           Verify the signature using the private key in "filename".

       -signature filename
           The actual signature to verify.

       -hmac key
           Create a hashed MAC using "key".

       -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 gost-mac
           algorithm, supported by ccgost engine. MAC keys and other options should be set via -macopt
           parameter.

       -macopt nm:v
           Passes options to MAC algorithm, specified by -mac key.  Following options are supported by both by
           HMAC and gost-mac:

           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.

           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.

       -rand file...
           A file or files containing random data used to seed the random number generator.  Multiple files can
           be specified separated by an OS-dependent character.  The separator is ; for MS-Windows, , for
           OpenVMS, and : for all others.

       [-writerand file]
           Writes random data to the specified file upon exit.  This can be used with a subsequent -rand flag.

       -fips-fingerprint
           Compute HMAC using a specific key for certain OpenSSL-FIPS operations.

       -engine id
           Use engine 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 or -engine_impl is also
           specified.

       -engine_impl
           When used with the -engine option, it specifies to also use engine id for digest operations.

       file...
           File or files to digest. If no files are specified then standard input is used.

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

NOTES

       The digest mechanisms that are available will depend on the options used when building OpenSSL.  The 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.

       When signing a file, 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 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 openssl.  Instead, use "xxd -r" or similar program to transform
       the hex signature into a binary signature prior to verification.

HISTORY

       The default digest was changed from MD5 to SHA256 in OpenSSL 1.1.0.  The FIPS-related options were
       removed in OpenSSL 1.1.0.

COPYRIGHT

       Copyright 2000-2019 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (the "License").  You may not use this file except in compliance with
       the License.  You can obtain a copy in the file LICENSE in the source distribution or at
       <https://www.openssl.org/source/license.html>.