openssl-dgst1ssl

Usage

Overview

This command output the message digest of a supplied file or files in hexadecimal, and also generates and verifies digital signatures using message digests.

The generic name, openssl 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 sub-command name. To see the list of supported algorithms, use "openssl list -digest-algorithms"

Options

-help

Print out a usage message.

-digest

Specifies name of a supported digest to be used. See option -list below :

-list

Prints out a list of supported message digests.

-c

Print out the digest in two digit groups separated by colons, only relevant if the -hex option is given as well.

-d, -debug

Print out BIO debugging information.

-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.

-xoflen length

Set the output length for XOF algorithms, such as shake128 and shake256. This option is not supported for signing operations.

For OpenSSL providers it is required to set this value for shake algorithms, since the previous default values were only set to supply half of the maximum security strength.

To ensure the maximum security strength of 128 bits, the xoflen for shake128 should be set to at least 32 (bytes). For compatibility with previous versions of OpenSSL, it may be set to 16, resulting in a security strength of only 64 bits.

To ensure the maximum security strength of 256 bits, the xoflen for shake256 should be set to at least 64 (bytes). For compatibility with previous versions of OpenSSL, it may be set to 32, resulting in a security strength of only 128 bits.

-r

Output the digest in the "coreutils" format, including newlines. Used by programs like sha1sum(1).

-out filename

Filename to output to, or standard output by default.

-sign filename|uri

Digitally sign the digest using the given private key.

Note that for algorithms that only support one-shot signing (such as Ed25519, ED448, ML-DSA-44, ML-DSA-65 andML-DSA-87) the digest must not be set. For these algorithms the input is buffered (and not digested) before signing. For these algorithms, if the input is larger than 16MB an error will occur.

-keyform DER|PEM|P12|ENGINE

The format of the key to sign with; unspecified by default. See openssl-format-options(1) for details.

-sigopt nm:v

Pass options to the signature algorithm during sign or verify operations. Names and values of these options are algorithm-specific and documented in "Signature parameters" in provider-signature(7).

-passin arg

The private key password source. For more information about the format of arg see openssl-passphrase-options(1).

-verify filename

Verify the signature using the public key in "filename". The output is either "Verified 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".

The openssl-mac(1) command should be preferred to using this command line option.

-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 the gost engine. MAC keys and other options should be set via -macopt parameter.

The openssl-mac(1) command should be preferred to using this command line option.

-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.

The openssl-mac(1) command should be preferred to using this command line option.

-fips-fingerprint

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

-rand files, -writerand file

See "Random State Options" in openssl(1) for details.

-engine id

See "Engine Options" in openssl(1). This option is deprecated.

The engine is not used for digests unless the -engine_impl option is used or it is configured to do so, see "Engine Configuration Module" in config(5).

-engine_impl id

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

-provider name

-provider-path path

-provparam [name:]key=value

-propquery propq

See "Provider Options" in openssl(1), provider(7), and property(7).

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
 or
 openssl md5 file.txt

To sign a file using SHA-256 with binary file output:

 openssl dgst -sha256 -sign privatekey.pem -out signature.sign file.txt
 or
 openssl 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 "openssl list -digest-algorithms" 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, this command 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.

The openssl-mac(1) command is preferred over the -hmac, -mac and -macopt command line options.