README file for Mercy 6.1

  http://www.cluefactory.org.uk/paul/mercy/

Mercy-6 is a 4096-bit block cipher designed for disk block encryption.
It is free from licensing restrictions, and all the source code here
is in the public domain; I know of no patent restrictions affecting
it.

This version of Mercy is that presented at the conference and described in
the proceedings.  All of this should be thoroughly portable to nearly
anything, but I've only actually tested it on my x86-based Debian 2.1 Linux
box using gcc and gcc 2.95.  

The source here is sufficient to time the cipher on your system.  It
will *not* encrypt any hard disks; it's meant to help assessment and
discussion of the cipher.  Work needed to make this part of a disk
encryption system includes not only hacking it into the kernel, but
also specifying some details such as endianness that the paper does
not address.  In any case, this revision of the cipher has now been
shown to have differential characteristics that make it somewhat
weaker than the key size would suggest, and thus a poor choice as it
stands.

Scott Fluhrer pointed out two bugs in the implementation of RC4 that
makes up the key schedule for version 6.0; these have been fixed to
make this version.

If you're reading this, please mail me and let me know:
mercy@paul.cluefactory.org.uk

enjoy,
Paul Crowley
11 August 2000