hmac256 - Compute an HMAC-SHA-256 MAC

       This  is  a standalone HMAC-SHA-256 implementation used to compute an HMAC-SHA-256 message authentication
       code.  The tool has originally been developed as a second implementation for Libgcrypt to allow comparing
       against the primary implementation and to be used for internal consistency checks.  It should not be used
       for sensitive data because no mechanisms to clear the stack etc are used.

       The code has been written in a highly portable manner and requires only a few standard definitions to  be
       provided in a config.h file.

       hmac256 is commonly invoked as

         hmac256 "This is my key" foo.txt

       This compute the MAC on the file ‘foo.txt’ using the key given on the command line.

hmac256 - Compute an HMAC-SHA-256 MAC

hmac256 understands these options:

       --binary
              Print  the  MAC  as  a  binary  string.  The default is to print the MAC encoded as lower case hex
              digits.

       --version
              Print version of the program and exit.

sha256sum(1)

Libgcrypt 1.11.0                                   2024-09-30                                         HMAC256(1)

hmac256 [--binary] key[FILENAME]