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OPENSSL-MAC(1SSL)                              OpenSSL                             OPENSSL-MAC(1SSL)



NAME
       openssl-mac - perform Message Authentication Code operations

SYNOPSIS
       openssl mac [-help] [-cipher] [-digest] [-macopt] [-in filename] [-out filename] [-binary]
       [-provider name] [-provider-path path] [-propquery propq] mac_name

DESCRIPTION
       The message authentication code functions output the MAC of a supplied input file.

OPTIONS
       -help
           Print a usage message.

       -in filename
           Input filename to calculate a MAC for, or standard input by default.  Standard input is
           used if the filename is '-'.  Files are expected to be in binary format, standard input
           uses hexadecimal text format.

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

       -binary
           Output the MAC in binary form. Uses hexadecimal text format if not specified.

       -cipher name
           Used by CMAC and GMAC to specify the cipher algorithm.  For CMAC it must be one of
           AES-128-CBC, AES-192-CBC, AES-256-CBC or DES-EDE3-CBC.  For GMAC it should be a GCM mode
           cipher e.g. AES-128-GCM.

       -digest name
           Used by HMAC as an alphanumeric string (use if the key contains printable characters
           only).  The string length must conform to any restrictions of the MAC algorithm.  To see
           the list of supported digests, use "openssl list -digest-commands".

       -macopt nm:v
           Passes options to the MAC algorithm.  A comprehensive list of controls can be found in
           the EVP_MAC implementation documentation.  Common parameter names used by
           EVP_MAC_CTX_get_params() are:

           key:string
               Specifies the MAC key as an alphanumeric string (use if the key contains printable
               characters only).  The string length must conform to any restrictions of the MAC
               algorithm.  A key must be specified for every MAC algorithm.

           hexkey:string
               Specifies the MAC key in hexadecimal form (two hex digits per byte).  The key length
               must conform to any restrictions of the MAC algorithm.  A key must be specified for
               every MAC algorithm.

           iv:string
               Used by GMAC to specify an IV as an alphanumeric string (use if the IV contains
               printable characters only).

           hexiv:string
               Used by GMAC to specify an IV in hexadecimal form (two hex digits per byte).

           size:int
               Used by KMAC128 or KMAC256 to specify an output length.  The default sizes are 32 or
               64 bytes respectively.

           custom:string
               Used by KMAC128 or KMAC256 to specify a customization string.  The default is the
               empty string "".

           digest:string
               This option is identical to the -digest option.

           cipher:string
               This option is identical to the -cipher option.

       -provider name
       -provider-path path
       -propquery propq
           See "Provider Options" in openssl(1), provider(7), and property(7).

       mac_name
           Specifies the name of a supported MAC algorithm which will be used.  To see the list of
           supported MAC's use the command "openssl list -mac-algorithms".

EXAMPLES
       To create a hex-encoded HMAC-SHA1 MAC of a file and write to stdout: \
        openssl mac -digest SHA1 \
                -macopt hexkey:000102030405060708090A0B0C0D0E0F10111213 \
                -in msg.bin HMAC

       To create a SipHash MAC from a file with a binary file output: \
        openssl mac -macopt hexkey:000102030405060708090A0B0C0D0E0F \
                -in msg.bin -out out.bin -binary SipHash

       To create a hex-encoded CMAC-AES-128-CBC MAC from a file:\
        openssl mac -cipher AES-128-CBC \
                -macopt hexkey:77A77FAF290C1FA30C683DF16BA7A77B \
                -in msg.bin CMAC

       To create a hex-encoded KMAC128 MAC from a file with a Customisation String 'Tag' and output
       length of 16: \
        openssl mac -macopt custom:Tag -macopt hexkey:40414243444546 \
                -macopt size:16 -in msg.bin KMAC128

       To create a hex-encoded GMAC-AES-128-GCM with a IV from a file: \
        openssl mac -cipher AES-128-GCM -macopt hexiv:E0E00F19FED7BA0136A797F3 \
                -macopt hexkey:77A77FAF290C1FA30C683DF16BA7A77B -in msg.bin GMAC

NOTES
       The MAC mechanisms that are available will depend on the options used when building OpenSSL.
       Use "openssl list -mac-algorithms" to list them.

SEE ALSO
       openssl(1), EVP_MAC(3), EVP_MAC-CMAC(7), EVP_MAC-GMAC(7), EVP_MAC-HMAC(7), EVP_MAC-KMAC(7),
       EVP_MAC-Siphash(7), EVP_MAC-Poly1305(7)

COPYRIGHT
       Copyright 2018-2021 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (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>.



3.0.2                                        2026-06-02                            OPENSSL-MAC(1SSL)