摘要: 用统计测试方法分析密码算法的完全性存在误差。为此,利用符号计算软件Mathematica 7.0,以明文和密钥比特为自变量,得到LBlock分组密码第1轮~第5轮输出的多项式表达式,结果显示,LBlock第5轮输出的任何比特至多与45个明文比特、49个密钥比特有关,说明5轮LBlock还未达到完全性。
关键词:
完全性,
分组密码,
LBlock密码,
多项式表示,
符号计算,
Mathematica软件
Abstract: There are errors in analyzing the completeness of a cryptographic algorithm by statistical testing method. By using the symbolic computation software Mathematica 7.0, the polynomial expressions(in terms of the plaintext bits and key bits) of the output of 1~5 round of the block cipher LBlock are obtained. The result shows that any bit of the output of the 5th round of LBlock depends on at most 45 plaintext bits and 49 key bits, which means that 5-round LBlock is not complete.
Key words:
completeness,
block cipher,
LBlock cipher,
polynomial expression,
symbolic computation,
Mathematica
中图分类号:
彭昌勇, 祝跃飞, 顾纯祥, 米顺强. 1~5轮LBlock的多项式表示及完全性分析[J]. 计算机工程, 2012, 38(9): 155-157,179.
BANG Chang-Yong, CHU Ti-Fei, GU Chun-Xiang, MI Shun-Jiang. Polynomial Expression and Completeness Analysis of 1~5 Round LBlock[J]. Computer Engineering, 2012, 38(9): 155-157,179.