查询词典 cipher

Chapter 4 presents five design criteria of S-boxes of block ciphers, develops a method of constructing large S-box by use of algebraic group operation, proves the balance property of these large S-box, tests the strict avalanche and independence of avalanche variables properties of S-boxes in NEA cipher, analyses the nonlinearity and best linear approximation of the S-box, and finally defines the differential of input/output of S-boxes of this cipher and analyses the distribution of them.

第二部分即第三章，提出了一种新的分组密码类NEA(NEA-4A，NEA-8A，NEA-4B，NEA-8B)，完整地描述了该密码类的加解密过程和密钥协议；证明了NEA-4B和NEA-8B的完全对合性和没有不动点的性质；分析了该密码类的安全特征；具体地介绍了实现该类密码的途径；给出了NEA-4A的计算机C语言程序和样本数据。

Using the cipher-byte produces a better dispersion of keys than just using the plain byte, but the plain byte must be included for this multiplication to have any security value as the cipher byte is available to a cracker.

使用加密字节的产生不仅仅是使用纯字节的密钥分散较好，但平原字节必须包含这个乘法有任何的加密字节的安全值，提供给饼干。

The validity of the provable security of counter with cipher block chaining message authentication code mode and cipher-based message authentication code mode was studied and proved. The illustrations of different communications' encryption have been developed.

对分组密码算法CCM、CMAC加密模式进行描述，用可证安全性理论对它们进行相关研究和证明，并对各种证明情况在不同通信环境下的使用作出说明。

In addition, algorithms used in PBE were discussed in details, including International Data Encryption Algorithm, Advanced Encryption Standard of U.S., safe Hash function named SHA-1, Pseudo Random Number Generator.The modes of operation in blok cipher,such as Electronic Code Book, Cipher Block Chaining, Cipfertext Feedback and Output Feedback,are described in the thesis.

采用DSP TMS320C5409汇编语言编制了以上各种算法，在DSP上实现了一个口令加密系统，数据加密速度达到3Mb/s以上，并实现密钥的安全管理，能满足个人PC机脱离主CPU加密大量数据的需要。

It must improve the commonly symmetrical key block cipher arithmetic for ensuring that the data length will not be increased after encryption: using forward shift bits mode in Triple DES with Two Keys; using cipher text stealing mode in RC5 with Cipher Block Chaining.

为保证加密后数据长度不变，应对常用的对称密钥分组密码算法以改进：双密钥三重DES加密采用向前挪位法，RC5密码分组链接加密采用密文窃取方式。

Chapter 2 clarifies the cryptographical foundation, which includes the symmetrical cipher technology, unsymmetrical cipher technology and digital envelope .

包括对称密码技术，非对称密码技术和数字信封技术，并详细分析了DES算法和RSA算法。

In essence, stream cipher is such a pseudorandom generator that its chaos sequence of output and random sequence are computational indistinguishability; and the aim in designing block cipher materially is to design a pseudorandom permutation which is computationally indistinguishable from random permutations.

实际上，序列密码本质上就是一个伪随机生成器G，其输出的乱数序列和随机序列是计算不可分辨的；而分组密码的设计目标实质上就是设计一个伪随机置换，它与随机置换是计算不可分辨的。

The S box was constituted with the multiplication inverse element affined transformation in GF(2) of all elements of limited field GF(28),with S box s nonlinear byte changed,ciphered text attained the ideal status of the even of difference and the linear of deviation,and increased the capability of the AES algorithm of anti beating the difference cipher of analysis and linear cipher of analysis.

S盒由有限域G F(28)上所有元素的乘法逆元及在域G F(2)上的仿射变换构成，经过S盒的非线性字节代换，密文的差分均匀性和线性偏差都达到较理想的状态，提高了A E S算法抗击差分密码分析及线性密码分析的能力。

The symmetric algorithm is a traditional algorithm, it is easy and efficient, and so it is still being popular used. The stream cIPher and the block cIPher are two part of the symmetric algorithm. The symmetric algorithm uses the key to control the key stream generator, and then the generator produces a random stream. We can get the cIPher by xor the message and the random stream by bit. In the field of communication and code, the stream cIPher has always been the key cIPher of the military affairs and foreign affairs.

对称密码体制分为序列密码和分组密码两类，序列密码以密钥控制密钥流发生器，产生一随机序列，用这个随机序列和明文信息逐位异或，就得到密文，其加密单元为比特。

For example, if the two methods used are the Playfair cipher and simple columnar transposition, if transposition is used first, the Playfair cipher can still be attacked, because it takes each input letter to a limited number of substitutes; if the Playfair cipher is used first, multiple anagramming, although now much more difficult, is still possible because a text enciphered by Playfair still has digraph frequencies marked well enough to allow a correct match to be detected.

例如，如果这两种方法用的是playfair密码和简单的柱状移位，如果移位是用第一， playfair密码仍然可以被攻击，因为它需要每个输入信有限数量的代用品；如果playfair密码是用来首先，多重anagramming ，虽然现在困难得多，仍然有可能因为一个文本加密由playfair仍然有向图的频率明显做得不够好，让一个正确的匹配，以进行检测。

By the time of its fall, most of the prisoners were writers who had written against the corruptions of the government.

到它被攻陷的时候，里面多数的犯人是写了反对政府贪污文章的作家。

The most obvious variation to ovum morphological character was that the color was changed from light green to sepiaceous in embryonic development, and all the ovums were almost hatched after 96h.

在胚胎发育过程中卵的形态特征最明显的变化是颜色从淡绿到深褐色，卵在发育96h后卵基本全部孵化。