Formulations of Some Bit Switching Functions in DES
In the data encryption standard (DES) algorithm, there exist several bit-switching functions, including permutations, ex pansion, and permuted choices.They are generally presented in the form of matrixes and realized by using table look-up technique in the implementation of the cryptosystem.This paper presents explicit formulas for the initial permutation IP, its inverse IP-1, the expansion function E, and the permuted choice PC_1.It also gives the program realizations of these functions in C++ applying these formulas.With the advantage of the omission of the storage space for these matrixes and the tedious inputs of tables in the imple mentations of DES, our experimental results shows that the ex plicit formulas are useful in some situations, such as wireless sen sor networks where the memory capacity is limited, especially when the size of file for encrypting is not too large, preferably smaller than 256KB.
data encryption standard bit-switching functions explicit formulas
YOU Lin YANG Yilin WEN Wanli
College of Communication Engineering,Hangzhou Dianzi University,Hangzhou 310018,Zhejiang,China
国内会议
秦皇岛
英文
402-406
2013-09-01（万方平台首次上网日期，不代表论文的发表时间）