Provided by: libgcrypt20-dev_1.8.3-1ubuntu1_amd64 bug


       hmac256 - Compute an HMAC-SHA-256 MAC


       hmac256 [--binary] key [FILENAME]


       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 understands these options:

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

              Print version of the program and exit.