Paper available on new cipher

[Matt Blaze <mab@research.att.com>]

Bruce Schneier and I have been designing a block cipher, called
"MacGuffin", based on a new variant of the standard Feistel (S-P)
network structure.  We are presenting a paper describing the cipher,
entitled "The MacGuffin Block Cipher Algorithm", at the
Leuven crypto algorithms workshop later this month.  Here's the
abstract:

\begin{abstract}
This paper introduces MacGuffin, a 64 bit ``codebook'' block cipher.
Many of its characteristics (block size, application domain,
performance and implementation structure) are similar to those of the
U.S. Data Encryption Standard (DES).  It is based on a Feistel
network, in which the cleartext is split into two sides with one side
repeatedly modified according to a keyed function of the other.
Previous block ciphers of this design, such as DES, operate on equal
length sides.  MacGuffin is unusual in that it is based on a {\em
generalized unbalanced Feistel network (GUFN)} in which each round of
the cipher modifies only 16 bits according to a function of the other
48.  We describe the general characteristics of MacGuffin architecture
and implementation and give a complete specification for the 32-round,
128-bit key version of the cipher.
\end{abstract}

A PostScript preprint of the paper is available via anonymous FTP from:
	ftp://research.att.com/dist/mab/mcg.ps

A forthcoming paper will discuss the characteristics GUFN structure
in more detail.

Comments and analysis greatly appreciated.

-matt