The fingerprinting code is derived from a package
which describes itself as follows

        Do you want a powerful, uniform interface to MD5, a standard
        CRC-32, Snefru-8, and a combined universal fingerprint, in
        highly efficient library form or as easy-to-use programs?
        That's what this package provides.  The code is freely reusable
        so you can distribute it along with your own applications.
        Have fun.

        fingerprint 0.50 package, beta.
        930809
        Daniel J. Bernstein, djb@silverton.berkeley.edu.

        Fingerprint produces a base-64-sanely-encoded fingerprint of
        its input.  There are no options. I imagine this fingerprint as
        something universal and permanent, which people will use
        forever. If the fingerprint is ever broken, I'd rather make an
        entirely new program than try to extend this one.

        A fingerprint is 76 characters long. What does it contain?
        Here's a list:

        1. A Snefru-8 (version 2.5, 8 passes, 512->256) hash.
           (Derived from the Xerox Secure Hash Function.)
        2. An MD5 hash, as per RFC 1321.
           (Derived from the RSADSI MD5 Message-Digest Algorithm.)
        3. A CRC checksum, as in the new cksum utility.
        4. Length modulo 2^40.

        The output format is not expected to be compatible with
        anything.