Arbitrary Bit Permutations in One or Two Cycles

Symmetric-key block ciphers encrypt data, providing data confidentiality over the public Internet. For inter-operability reasons, it is desirable to support a variety of symmetric-key ciphers efficiently. We show the basic operations performed by a variety of symmetric-key cryptography algorithms. Of these basic operations, only bit permutation is very slow using existing processors, followed by integer multiplication. New instructions have been proposed recently to accelerate bit permutations in general-purpose processors, reducing the instructions needed to achieve an arbitrary n-bit permutation from O(n) to O(log(n)). However, the serial data-dependency between these log(n) permutation instructions prevents them from being executed in fewer than log(n) cycles, even on superscalar processors. Since application specific instruction processors (ASIPs) have fewer constraints on maintaining standard processor datapath and control conventions, can we achieve even faster permutations? In ...

• Type: Conference
• Year: 2003
• Where: ASAP
• Authors: Zhijie Shi, Xiao Yang, Ruby B. Lee
• Keywords: Arbitrary 64-bit Permutations, ASAP 2003, Bit Permutations, Distributed And Parallel Computing, Permutation