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

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 2000-2021 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>.