Package of utility functions to do hash calculation and HMAC
signature generation for data authentication.

See RFC 2104 (and examples in RFC 2202) for more details on HMAC

The package is minimally documented, but usable.
See examples in the "misc" dir.

Input data, can be a string or a resource created using
fopen/fsocket/gzopen/bzopen/popen (or its stream equivalent).
