DES algorithm analysis
（DES：Data Encryption Standard）。
https://www.cnblogs.com/songwenlong/p/5944139.html
https://www.cnblogs.com/lixiaoxu/articles/7736917.html
https://www.cnblogs.com/luop/p/4366902.html
3 Other Cipher Algorithms Three cipher algorithms, DES, AES, and Simon, have been introduced
recently . They are all block cipher algorithms. We will introduce other block cipher algorithms, stream cipher algorithms, and hash functions (Hash algorithm) when there is time in the future. Readers who are interested can refer to "Cryptography and Network Security - Principles and Practice" and related information on the Internet. The algorithm principles are basically the same.
4 References
[1] William Stallings; translated by Wang Zhangyi et al. Cryptography and Network Security - Principles and Practice (Fifth Edition) [M]. Beijing: Electronic Industry Press, 2012.1.
[2] http://en.wikipedia.org/wiki/Data_Encryption_Standard
[3] http://en.wikipedia.org/wiki/Feistel_cipher
[4] https://github.com/tarequeh/DES
http://www.hankcs.com/security/des-algorithm-illustrated.html Important
Translated from J. Orlin Grabbe's masterpiece "DES Algorithm Illustrated", many foreign universities use this article as supplementary material, which can be used as a guide for understanding the DES algorithm Best introductory manual.
https://www.cnblogs.com/luop/p/4366902.html
Note the meaning of symmetric keys:
https://blog.csdn.net/wyq_841943/article/details/50157363
https://blog.csdn.net/White_Idiot/article/details/67634872 The picture is good
https://blog.csdn.net/yxtxiaotian/article/details/52025653 The analysis is good, and it is further organized on this basis
https://www.cnblogs.com/lixiaoxu/articles/7736917.html
https://en.wikipedia.org/wiki/Data_Encryption_Standard
Detailed Explanation and Code of DES Algorithm - IP Replacement
https://blog.csdn.net/bcbobo21cn/article/details/48626149
The 58th digit of the input will be changed to the first place, the 50th place to the 2nd place, ..., and so on By analogy, the last digit is the original 7th digit. L0 and R0 are the two parts after transposition output, L0 is the left 32 bits of the output, R0 is the right 32 bits, for example
For example, if the input value before the replacement is D1D2D3…D64, the result after the initial replacement is: L0=D58D50…D8; R0=D57D49…D7.
Initial Permutation (IP) : Initial Permutation
Permuted Choice 1 (PC-1)
Permuted Choice 2 (PC-2)
Expansion (E)
Substitution Box 1 (S[1])
Final Permutation (IP**-1)
Permutation P
Security System (1) - Detailed Explanation of DES Algorithm