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assignmentutor-lab™ 为您的留学生涯保驾护航 在代写密码学cryptography theory方面已经树立了自己的口碑, 保证靠谱, 高质且原创的统计Statistics代写服务。我们的专家在代写密码学cryptography theory代写方面经验极为丰富，各种代写密码学cryptography theory相关的作业也就用不着说。

• Statistical Inference 统计推断
• Statistical Computing 统计计算
• (Generalized) Linear Models 广义线性模型
• Statistical Machine Learning 统计机器学习
• Longitudinal Data Analysis 纵向数据分析
• Foundations of Data Science 数据科学基础

## 数学代写|密码学代写cryptography theory代考|Critical to Block Ciphers

The first is one you should study s-box design is a reason you should already be aware of: that $s$-boxes form a major part of most block ciphers. It would be impossible to thoroughly study symmetric cryptography without knowing a bit about s-boxes. If you do not understand s-boxes, then there is a portion of most block ciphers that you must treat as simply a black-box, with no real understanding of what happens inside nor why. This fact should be readily apparent from the algorithms you studied in Chaps. 6 and 7. And as has already been pointed out in this book, s-boxes are the primary source for non-linearity in modern block ciphers.
Consider Feistel ciphers that you studied in Chap. 6. The XOR operation forms a part of every Feistel cipher. In most round functions there is an XOR with the round key, and of course there is a transposition of the two halves of the block each round. But the real substance of encrypting comes from the s-box. Without it, Feistel ciphers would be extremely weak, and simply not acceptable for modern use. In fact, without the s-boxes, many block ciphers would not be much better than combining a substitution cipher such as Caesar with a transposition cipher such as Rail-Fence and executing it several times.

## 数学代写|密码学代写cryptography theory代考|Designing Ciphers

Secondly, should you ever be involved in the design of a symmetric cipher, you will need to design s-boxes. These are often key to the security of a symmetric cipher. It will be important to understand the principles of s-box design.

Typically designing your own cipher is an extremely bad idea. This is because you are unlikely to produce something that is sufficiently secure. It is most probable that in attempting such a task you will create a cipher that is, at best much weaker than currently used algorithms. However, someone must create the new ciphers that appear from time to time. So clearly some people do create new ciphers that are secure. However, the creators of real algorithms that are actually secure enough are people with a very substantial mathematical background and who have studied existing algorithms in quite some depth. My recommendation is that you first carefully study cryptography for several years, looking at existing ciphers in detail. Before considering developing your own cipher, you must thoroughly understand a wide range of existing ciphers. Consider the inventors of the algorithms you have seen so far in Chaps. 6 and 7. All had extensive related education, such as mathematics, and all have worked in the field of cryptography for many years. This is not a field where a novice is likely to make a substantive contribution. Becoming a cryptographer is a lengthy process. This book would just be the first step on that journey. Then, after careful and in-depth study, if you do feel compelled to create a new cipher, submit it to the peer review process so other experts in the field can evaluate your idea.

It is difficult to overemphasize the importance of the s-box in designing a block cipher. Anna Grocholewska-Czurylo, in her paper “Cryptographic properties of modified AES-like S-boxes,” describes the importance of s-boxes as follows “Sbox design is usually the most important task while designing a new cipher. This is because an S-box is the only non-linear element of the cipher upon which the whole cryptographic strength of the cipher depends. New methods of attacks are constantly being developed by researchers, so S-box design should always be one step ahead of those pursuits to ensure cipher’s security.” (Grocholewska-Czuryło 2011).

# 密码学代写

## 数学代写|密码学代写cryptography theory代考|Critical to Block ciers

. crypgraphy -theory . crypgraphy -theory . crypgraphy -theory

## 数学代写|密码学代写cryptography theory代考|Designing Ciphers

s-box在分组密码设计中的重要性再怎么强调都不为过。Anna Grocholewska-Czurylo在她的论文《改进的AES-like s-box的密码特性》中描述了s-box的重要性:“Sbox设计通常是设计新密码时最重要的任务。这是因为s框是密码中唯一的非线性元素，整个密码强度依赖于它。研究人员不断开发新的攻击方法，因此s盒设计应该始终领先于这些追求，以确保密码的安全性。”(grocholewska – czuryso 2011).

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## MATLAB代写

MATLAB 是一种用于技术计算的高性能语言。它将计算、可视化和编程集成在一个易于使用的环境中，其中问题和解决方案以熟悉的数学符号表示。典型用途包括：数学和计算算法开发建模、仿真和原型制作数据分析、探索和可视化科学和工程图形应用程序开发，包括图形用户界面构建MATLAB 是一个交互式系统，其基本数据元素是一个不需要维度的数组。这使您可以解决许多技术计算问题，尤其是那些具有矩阵和向量公式的问题，而只需用 C 或 Fortran 等标量非交互式语言编写程序所需的时间的一小部分。MATLAB 名称代表矩阵实验室。MATLAB 最初的编写目的是提供对由 LINPACK 和 EISPACK 项目开发的矩阵软件的轻松访问，这两个项目共同代表了矩阵计算软件的最新技术。MATLAB 经过多年的发展，得到了许多用户的投入。在大学环境中，它是数学、工程和科学入门和高级课程的标准教学工具。在工业领域，MATLAB 是高效研究、开发和分析的首选工具。MATLAB 具有一系列称为工具箱的特定于应用程序的解决方案。对于大多数 MATLAB 用户来说非常重要，工具箱允许您学习应用专业技术。工具箱是 MATLAB 函数（M 文件）的综合集合，可扩展 MATLAB 环境以解决特定类别的问题。可用工具箱的领域包括信号处理、控制系统、神经网络、模糊逻辑、小波、仿真等。

assignmentutor™您的专属作业导师
assignmentutor™您的专属作业导师