GitLab

RPMB requires digital signature of the message.  Take the implementation
of HMAC SHA256 from this place https://github.com/ogay/hmac.git



Actually this is BSD license, IANAL but according to my understanding
nothing terrible will happen if we provide all the original copyrights.
Signed-off-by: Roman Pen <r.peniaev@gmail.com>
Cc: Ben Gardiner <bengardiner@nanometrics.ca>
Signed-off-by: Chris Ball <chris@printf.net>