查询词典 a 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。

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 diffusion structure has important impact on the rate of the diffusion and safety intensity for block cipher.Using the linear transform which has branch numbers as large as possible as the diffusion structure is a main method to devise block cipher.The linear transform is usually achieved by constructing the invertible matrix.

扩散结构的好坏直接影响了分组密码的扩散速度和安全强度，以分支数尽可能大的线性变换为分组密码算法的扩散结构是设计分组密码的一种重要方法，线性变换的构造可通过可逆矩阵的构造完成。

This invention discloses a safety authenticating method for PC customer end including PC customer end presents registration request to a service via ID number and cipher, the server makes the first authentication based on customer ID number and the cipher to generate a field of reauthentication if it's passed to be fed back to PC customer end along with the finished authentication message; when PC customer end makes calls, it will send ID number and field of reauthentication during registration to media gate controller which transfer the ID number field of reauthentication to be server for second time authentication and refuse the calling if it's not passed, or receive the calling and feeding back the called information.

要约 本发明公开了一种PC客户端的安全认证方法，包括：PC客户端通过用户ID号码和密码，向服务器发起登录请求；服务器根据用户ID号码和密码进行第一次认证，若认证通过，生成一个用于再次认证的字段，并随认证通过消息返回给PC客户端；当PC客户端发起呼叫时，将用户ID号码和登录时获得的再次认证的字段一起传送给媒体网关控制器；媒体网关控制器将该用户ID号码、再次认证的字段一起传送给服务器进行第二次的认证，若认证没有通过，则拒绝呼叫，否则接受呼叫返回被叫信息。

The block cipher with a substitution permutation network is the best known and widely used block cipher system.

包含代替置换网络的分组密码是一种广泛使用的分组密码系统。

One of the simplest examples of a substitution cipher is the Caesar cipher, which is said to have been used by Julius Caesar to communicate with his army.

对一替代密码的一个最简单的例子是凯撒密码，据说是被凯撒用于与他的军队。

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。

And since anyone can create a cipher that he believes to be secure, this means that cryptographers should only look at ciphers created by people whose opinions are worth something.

由于每个人都可以创造一个密码算法并相信它是安全，这意味着密码学家只会看那些其观点具有某种价值的人们创造的密码算法。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。