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Description: 主要内容：DES加密算法，里面采用CBC和EBC两种加密结构，实行分组加密。-main elements : DES encryption algorithm, and they used EBC two CBC encryption, and carrying out the packet encryption.
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Size: 5120 |
Author: 西们子 |
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Description: Playfair Cipher
1.not even the large number of keys in a monoalphabetic cipher provides security
2.one approach to improving security was to encrypt multiple letters
3.the Playfair Cipher is an example
4.invented by Charles Wheatstone in 1854,but named after his friend Baron Playfair
Playfair Key Matrix
1.a 5X5 matrix of letters based on a keyword
2.fill in letters of keyword (sans duplicates)
3.fill rest of matrix with other letters
Encrypting and Decrypting
-plaintext is encrypted two letters at a time
1. if a pair is a repeated letter, insert filler like X’
2. if both letters fall in the same row, replace each with letter to right (wrapping back to start from end)
3. if both letters fall in the same column, replace each with the letter below it (again wrapping to top from
bottom)
4. otherwise each letter is replaced by the letter in the same row and in the column of the other letter of the pair -Playfair Cipher
1.not even the large number of keys in a monoalphabetic cipher provides security
2.one approach to improving security was to encrypt multiple letters
3.the Playfair Cipher is an example
4.invented by Charles Wheatstone in 1854,but named after his friend Baron Playfair
Playfair Key Matrix
1.a 5X5 matrix of letters based on a keyword
2.fill in letters of keyword (sans duplicates)
3.fill rest of matrix with other letters
Encrypting and Decrypting
-plaintext is encrypted two letters at a time
1. if a pair is a repeated letter, insert filler like X’
2. if both letters fall in the same row, replace each with letter to right (wrapping back to start from end)
3. if both letters fall in the same column, replace each with the letter below it (again wrapping to top from
bottom)
4. otherwise each letter is replaced by the letter in the same row and in the column of the other letter of the pair
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Size: 133120 |
Author: 黃文岩 |
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Description: The cover is a modified set of 17 cipher alphabets the black background color is symbolic of the U.S. State
Department’s Black Chamber in which American cryptanalysis originated in the early part of the 20th-century.
It is technically defective in several aspects (i) fewer than 26 letters in each row are displayed and (ii) repeated
letters occur in the rows containing the word CRYPTOGRAPHY and my name.-The cover is a modified set of 17 cipher alphabets the black background color is symbolic of the U.S. State
Department’s Black Chamber in which American cryptanalysis originated in the early part of the 20th-century.
It is technically defective in several aspects (i) fewer than 26 letters in each row are displayed and (ii) repeated
letters occur in the rows containing the word CRYPTOGRAPHY and my name.
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Size: 8783872 |
Author: YY |
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Description: Columnar is a transposition cipher. It is used in cryptography. The message is written as letters in a row and it is coded by reading out the letter columnwise.
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Size: 1024 |
Author: aurora |
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Description: 置换密码算法的原理是不改变明文字符，只将字符在明文中的排列顺序改变，从而实现明文信息的加密。置换密码也叫换位密码。
试编程实现矩阵换位密码。它的加密方法是将明文中的字母按照给定的顺序安排在一个矩阵中，然后用根据密钥提供的顺序重新组合矩阵中的字母，形成密文。例如，明文为attack begins at five，密钥为cipher，将明文按照每行6个字母的形式排在矩阵中，如下形式：
a t t a c k
b e g i n s
a t f i v e
根据密钥cipher中各字母在字母表中出现的先后顺序，给定一个置换：
根据上面的置换，将原有矩阵中的字母按照第1、4、5、3、2、6的顺序排列，则有下列形式：
a a c t t k
b i n g e s
a i v f t e
从而得到密文：aacttkbingesaivfte
解密过程类推。
-The principle of permutation cipher algorithm is to change the order of characters in plaintext without changing the plaintext characters, so as to realize the encryption of plaintext information. Permutation cipher is also called transposition cipher.
Programming to achieve matrix transposition password. Its encryption method is that the letters in the plaintext are arranged in a matrix according to a given order, and then the letters in the matrix are re assembled in the order provided by the key to form a ciphertext. For example, the plaintext is attack begins at five, the key is cipher, and the plaintext is placed in the matrix in the form of 6 letters per row, as follows:
A, t, t, a, C, K
B, e, G, I, N, s
A, t, F, I, V, e
According to the order in which the letters in the key cipher appear in the alphabet, a permutation is given:
According to the above permutation, the letters in the original matrix are arranged in the order of first, fourth, fifth, 3, 2 and 6, and the follo
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Size: 1024 |
Author: 1 |
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