摘要
论文针对受噪声干扰的单字母加密方式的密文设计了一种破译算法,该算法建立在频率分析的基础上,通过统计密文中的字母频率制作出字频表,联合受噪声干扰的误码率得出新的字频表,将一些非常相似的字频表分组存放,求出它们的排列情况,将这些新的字频表与经过大量文献统计出的英文字频表进行对照,生成若干的疑似密码表。利用穷举方式根据疑似密码表还原出若干的疑似明文。利用LZW算法对大量真实文本进行压缩生成LZW压缩编码表,利用压缩编码表对生成的疑似明文进行压缩,根据LZW算法的原理和英文语法和词汇特性,得出经过LZW算法压缩后长度最短的明文即为真实明文,这种压缩编码的验证方式非常高效。
In this paper,aiming at the single-letter encrypted ciphertext in noise,a deciphered algorithm is designed.The algorithm is based on frequency analysis.Through statistical ciphertext letter frequencies a word frequency table is produced.BER(bit error rate)in noise is combined to draw a new word frequency table.Similar word frequency tables are made to packet storage.The arrangement of them is determined.These new word frequency table and the English word frequency table out of literature statistcs are compared.Several suspected password lists are generated.Reducing the use of exhaustive way a number of suspected plaintext password table according suspected.LZW algorithm is used to a large number of real text compression generate LZW compression coding table.Compression encoding table is used for compressing suspected plaintext generation.Accordance with the principles of LZW algorithm and characteristics of English grammar and vocabulary.After the LZW compression algorithm derived shortest plain is truth plaintext.Compression coding is very efficient way to verify.
作者
钱宇环
范洪博
QIAN Yuhuan;FAN Hongbo(School of Information Engineering and Automation,Kunming University of Science and Technology,Kunming 650500)
出处
《计算机与数字工程》
2018年第4期686-688,749,共4页
Computer & Digital Engineering
关键词
LZW算法
压缩编码
频率分析
LZW algorithm
compression coding
frequency analysis
