The MacGuffin block cipher algorithm

  • Matt Blaze
  • Bruce Schneier
Session 2: Block Ciphers-Design
Part of the Lecture Notes in Computer Science book series (LNCS, volume 1008)


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 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.


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Copyright information

© Springer-Verlag Berlin Heidelberg 1995

Authors and Affiliations

  • Matt Blaze
    • 1
  • Bruce Schneier
    • 2
  1. 1.AT&T Bell LaboratoriesHolmdelUSA
  2. 2.Counterpane SystemsOak ParkUSA

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