DES加密算法详解

DES加密算法详解- -

对加密解密一直挺喜欢的，可还是没有怎么好好学习过，希望这是一个好的开始。

在网上搜了一下关于DES的说明，发现有些杂乱，所以还是有必要整合一下。

写了一点代码，还没有完成，不过，还不能编译通过，^_^

刚看了一下，发现还是说得够模糊的，有机会再整理一下。

昏倒，一直运行不对，今天才仔细查出来，原来问题是出在Des_Data_P(const _b32&

input, _b32 output),

我的output用了传值调用，失败呀。应该是Des_Data_P(const _b32& input, _b32

& output)

DES算法的入口参数有三个：

Key, Data, Mode

Key 为64bit密钥， Data为64bit数据，Mode为加密还是解密。

DES算法的过程:

1. 对输入的密钥进行变换。

用户的64bit密钥，其中第8， 16， 24， 32， 40， 48， 56， 64位是校验位，

使得每个密钥都有奇数个1。所以密钥事实上是56位。对这56位密钥进行如下表的换位。

57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18, 10, 2, 59, 51, 43,

35, 27, 19, 11, 3, 60, 52, 44, 36,

63, 55, 47, 39, 31, 23, 15, 7, 62, 54, 46, 38, 30, 22, 14, 6, 61, 53, 45,

37, 29, 21, 13, 5, 28, 20, 12, 4,

表的意思是第57位移到第1位，第49位移到第2位，...... 以此类推。变换后得到56b

it数据，将它分成两部分，C[0][28], D[0][28]。

2. 计算16个子密钥，计算方法C[i][28] D[i][28]为对前一个C[i-1][28], D[i-1][28]

做循环左移操作。16次的左移位数如下表:

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 （第i次)

1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 (左移位数)

3. 串联计算出来的C[i][28] D[i][28] 得到56位，然后对它进行如下变换得到48位子

密钥K[i][48]

14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10, 23, 19, 12, 4, 26, 8, 1

6, 7, 27, 20, 13, 2,

41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48, 44, 49, 39, 56, 34, 53, 4

6, 42, 50, 36, 29, 32,

表的意思是第14位移到第1位，第17位移到第2位，以此类推。在此过程中，发现第9，

18，22，25， 35，38，43，54位丢弃。

4. 对64bit的明文输入进行换位变换。换位表如下:

58, 50, 12, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4,

62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48, 40, 32, 24, 16, 8,

57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19, 11, 3,

61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7

表的意思就是第一次变换时，第58位移到第1位，第50位移到第2位，...... 依此类推。

得到64位数据，将这数据前后分成两块L[0][32], R[0][32]。

5. 加密过程，对R[i][32]进行扩展变换成48位数，方法如下， 记为E(R[i][32])

32, 1, 2, 3, 4, 5,

4, 5, 6, 7, 8, 9,

8, 9, 10, 11, 12, 13,

12, 13, 14, 15, 16, 17,

16, 17, 18, 19, 20, 21,

20, 21, 22, 23, 24, 25,

24, 25, 26, 27, 28, 29,

28, 29, 30, 31, 32, 1,

6. 将E(R[i][32])与K[i][48]作异或运算，得到48位数，将48位数顺序分成8份，6

位一份，B[8][6]。

7. 使用S[i]替换B[i][6]。过程如下: 取出B[i][6]的第1位和第6位连成一个2位数m，

m就是S[i]中对应的行数(0-3)，取出B[i][6]的第2到第5位连成一个4位数n(0-15)，

n就是S[i]中对应的列数，用S[i][m][n]代替B[i][6]。S是4行16列的对应表，里面是

4位的数，一共有8个S，定义如下:

S[1]:

14,4,13,1,2,15,11,8,3,10,6,12,5,9,0,7,

0,15,7,4,14,2,13,1,10,6,12,11,9,5,3,8,

4,1,14,8,13,6,2,11,15,12,9,7,3,10,5,0,

15,12,8,2,4,9,1,7,5,11,3,14,10,0,6,13,

S[2]:

15,1,8,14,6,11,3,4,9,7,2,13,12,0,5,10,

3,13,4,7,15,2,8,14,12,0,1,10,6,9,11,5,

0,14,7,11,10,4,13,1,5,8,12,6,9,3,2,15,

13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9,

S[3]:

10,0,9,14,6,3,15,5,1,13,12,7,11,4,2,8,

13,7,0,9,3,4,6,10,2,8,5,14,12,11,15,1,

13,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7,

1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12,

S[4]:

7,13,14,3,0,6,9,10,1,2,8,5,11,12,4,15,

13,8,11,5,6,15,0,3,4,7,2,12,1,10,14,9,

10,6,9,0,12,11,7,13,15,1,3,14,5,2,8,4,

3,15,0,6,10,1,13,8,9,4,5,11,12,7,2,14,

S[5]:

2,12,4,1,7,10,11,6,8,5,3,15,13,0,14,9,

14,11,2,12,4,7,13,1,5,0,15,10,3,9,8,6,

4,2,1,11,10,13,7,8,15,9,12,5,6,3,0,14,

11,8,12,7,1,14,2,13,6,15,0,9,10,4,5,3,

S[6]:

12,1,10,15,9,2,6,8,0,13,3,4,14,7,5,11,

10,15,4,2,7,12,9,5,6,1,13,14,0,11,3,8,

9,14,15,5,2,8,12,3,7,0,4,10,1,13,11,6,

4,3,2,12,9,5,15,10,11,14,1,7,6,0,8,13,

S[7]:

4,11,2,14,15,0,8,13,3,12,9,7,5,10,6,1,

13,0,11,7,4,9,1,10,14,3,5,12,2,15,8,6,

1,4,11,13,12,3,7,14,10,15,6,8,0,5,9,2,

6,11,13,8,1,4,10,7,9,5,0,15,14,2,3,12,

S[8]:

13,2,8,4,6,15,11,1,10,9,3,14,5,0,12,7,

1,15,13,8,10,3,7,4,12,5,6,11,0,14,9,2,

7,11,4,1,9,12,14,2,0,6,10,13,15,3,5,8,

2,1,14,7,4,10,8,13,15,12,9,0,3,5,6,11,

8. 将从B[i][6]经过S得到的8个4位数连起来得到32位数。对这个数进行如下变换:

16,7,20,21,29,12,28,17, 1,15,23,26, 5,18,31,10,

2,8,24,14,32,27, 3, 9,19,13,30, 6,22,11, 4,25,

得到的结果与L[i][32]作异或运算，把结果赋给R[i][32]。

9. 把R[i-1][32]的值赋给L[i]，从5开始循环。直到K[16][48]结束。

10. 将最后的L,R合并成64位，然后进行如下转化得到最后的结果。这是对第4步的一

个逆变化。

40, 8, 48, 16, 56, 24, 64, 32,

39, 7, 47, 15, 55, 23, 63, 31,

38, 6, 46, 14, 54, 22, 62, 30,

37, 5, 45, 13, 53, 21, 61, 29,

36, 4, 44, 12, 52, 20, 60, 28,

35, 3, 43, 11, 51, 19, 59, 27,

34, 2, 42, 10, 50, 18, 58, 26,

33, 1, 41, 9, 49, 17, 57, 25

以上是Des的加密过程，解密过程同样，只需要把16个子密钥K[i][48]的顺序颠倒过来

就行了。

对应于第1-3的key生成过程：/wikipedia/en/thumb/

3/3f/

对应于第4步开始：/wikipedia/en/thumb/f/fd/250px

-

对应于第5步开始的循环操作：/wikipedia/en/thumb/

1/1b/

代码:

/* filename: gy_

*/

/*

* Some of codes are copyed from which is written by Eri

cYoung(*************.au)

* You can get the lib from ftp:///pub/Crypto/DES/,

*/

#include "stdafx.h"

#include < bitset >

#include < vector >

#include < string >

#include < iostream >

using namespace std;

//using namespace gy;

typedef bitset< 4 > _b4;

typedef bitset< 6 > _b6;

typedef bitset< 8 > _b8;

typedef bitset< 28 > _b28;

typedef bitset< 32 > _b32;

typedef bitset< 48 > _b48;

typedef bitset< 56 > _b56;

typedef bitset< 64 > _b64;

typedef vector< _b8 > _vb8;

typedef vector< _b48 > _vb48;

typedef vector< _b64 > _vb64;

namespace {

const unsigned char odd_parity[256]={

1, 1, 2, 2, 4, 4, 7, 7, 8, 8, 11, 11, 13, 13,

14, 14,

16, 16, 19, 19, 21, 21, 22, 22, 25, 25, 26, 26, 28, 2

8, 31, 31,

32, 32, 35, 35, 37, 37, 38, 38, 41, 41, 42, 42, 44, 4

4, 47, 47,

49, 49, 50, 50, 52, 52, 55, 55, 56, 56, 59, 59, 61, 6

1, 62, 62,

64, 64, 67, 67, 69, 69, 70, 70, 73, 73, 74, 74, 76, 7

6, 79, 79,

81, 81, 82, 82, 84, 84, 87, 87, 88, 88, 91, 91, 93, 9

3, 94, 94,

97, 97, 98, 98,100,100,103,103,104,104,107,107,109,10

9,110,110,

112,112,115,115,117,117,118,118,121,121,122,122,124,1

24,127,127,

128,128,131,131,133,133,134,134,137,137,138,138,140,1

40,143,143,

145,145,146,146,148,148,151,151,152,152,155,155,157,1

57,158,158,

161,161,162,162,164,164,167,167,168,168,171,171,173,1

73,174,174,

176,176,179,179,181,181,182,182,185,185,186,186,188,1

88,191,191,

193,193,194,194,196,196,199,199,200,200,203,203,205,2

05,206,206,

208,208,211,211,213,213,214,214,217,217,218,218,220,2

20,223,223,

224,224,227,227,229,229,230,230,233,233,234,234,236,2

36,239,239,

241,241,242,242,244,244,247,247,248,248,251,251,253,2

53,254,254

const int keyperm_table56[56] = {

57, 49, 41, 33, 25, 17, 9, 1,

58, 50, 42, 34, 26, 18, 10, 2,

59, 51, 43, 35, 27, 19, 11, 3,

60, 52, 44, 36, 63, 55, 47, 39,

};

};

31, 23, 15, 7, 62, 54, 46, 38,

30, 22, 14, 6, 61, 53, 45, 37,

29, 21, 13, 5, 28, 20, 12, 4

const int keycompperm_table[48] = {

};

14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10,

23, 19, 12, 4, 26, 8, 16, 7, 27, 20, 13, 2,

41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48,

44, 49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32

const int keyshift_table[16] = {

};

1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1

const int datainitperm_table[64] = {

};

58, 50, 42, 34, 26, 18, 10, 2,

60, 52, 44, 36, 28, 20, 12, 4,

62, 54, 46, 38, 30, 22, 14, 6,

64, 56, 48, 40, 32, 24, 16, 8,

57, 49, 41, 33, 25, 17, 9, 1,

59, 51, 43, 35, 27, 19, 11, 3,

61, 53, 45, 37, 29, 21, 13, 5,

63, 55, 47, 39, 31, 23, 15, 7

const int dataexpperm_table[48] = {

32, 1, 2, 3, 4, 5,

};

4, 5, 6, 7, 8, 9,

8, 9, 10, 11, 12, 13,

12, 13, 14, 15, 16, 17,

16, 17, 18, 19, 20, 21,

20, 21, 22, 23, 24, 25,

24, 25, 26, 27, 28, 29,

28, 29, 30, 31, 32, 1

const int datasbox_table[8][4][16] = {

{

{14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5,

9, 0, 7},

{0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9,

5, 3, 8},

{4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 1

0, 5, 0},

{15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0,

6, 13},

},

{

{15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0,

5, 10},

{3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9,

11, 5},

{0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3,

2, 15},

{13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5,

14, 9},

},

{

4, 2, 8},

15, 1},

14, 7},

2, 12},

4, 15},

14, 9},

2, 8, 4},

2, 14},

14, 9},

9, 8, 6},

0, 14},

{10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11,

{13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11,

{13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10,

{1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5,

},

{

{7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12,

{13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10,

{10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5,

{3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7,

},

{

{2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0,

{14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3,

{4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3,

4, 5, 3},

5, 11},

1, 3, 8},

11, 6},

8, 13},

0, 6, 1},

5, 8, 6},

5, 9, 2},

3, 12},

12, 7},

4, 9, 2},

{11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10,

},

{

{12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7,

{10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 1

{9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13,

{4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0,

},

{

{4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 1

{13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 1

{1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0,

{6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2,

},

{

{13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0,

{1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 1

{7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15,

3, 5, 8},

{2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5,

6, 11},

const int datapperm_table[32] = {

16, 7, 20, 21, 29, 12, 28, 17, 1, 15, 23, 26, 5, 18,

};

}

31, 10,

25

const int datafp_table[64] = {

40, 8, 48, 16, 56, 24, 64, 32, 39, 7, 47, 15, 55, 23,

};

2, 8, 24, 14, 32, 27, 3, 9, 19, 13, 30, 6, 22, 11, 4,

63, 31,

38, 6, 46, 14, 54, 22, 62, 30, 37, 5, 45, 13, 53, 21,

61, 29,

36, 4, 44, 12, 52, 20, 60, 28, 35, 3, 43, 11, 51, 19,

59, 27,

34, 2, 42, 10, 50, 18, 58, 26, 33, 1, 41, 9, 49, 17,

57, 25

template < size_t _NB >

void rotateleft_bitset(bitset< _NB >& input, size_t step)

{

bitset< _NB > tmp = input;

};

step)

}

input <<= step;

tmp >>= _NB - step;

input |= tmp;

template < size_t _NB >

void rotateright_bitset(bitset< _NB >& input, size_t

{

}

bitset< _NB > tmp = input;

input >>= step;

tmp <<= _NB - step;

input |= tmp;

template < class Input, class Output, class Table>

void Des_Permutation( const Input& input, Output& output, con

st Table& table, size_t TableSize)

void Des_Key_Permutation1(const _b64& input, _b56& output)

{

Des_Permutation(input, output, keyperm_table56, sizeo

{

}

for (size_t i = 0; i < TableSize; ++i) {

}

output[i] = input[ table[i]-1 ];

f(keyperm_table56)/sizeof(int));

}

void Des_Key_CompPerm(const _b56& input, _b48& output)

{

Des_Permutation(input, output, keycompperm_table, siz

eof(keycompperm_table)/sizeof(int));

for (int i = 0; i < 16; ++i) {

void Des_Key_Shift(_b56& key56, size_t step)

{

}

void Des_Key_Generate(const _b64& key, _vb48& subkey)

{

_b56 tmp56;

Des_Key_Permutation1(key, tmp56);

_b28 l28, r28;

int i;

for (i = 0; i < 28; ++i) {

}

rotateleft_bitset(l28, step);

rotateleft_bitset(r28, step);

for (i = 0; i < 28; ++i) {

}

key56[i] = r28[i];

key56[28+i] = l28[i];

r28[i] = key56[i];

l28[i] = key56[28+i];

}

}

}

_b48 tmp48;

Des_Key_Shift(tmp56, keyshift_table[i]);

Des_Key_CompPerm(tmp56, tmp48);

cout << "Key: " << tmp48 << endl;

_back(tmp48);

void Des_Char_To_Binary(char c, string& binary)

{

}

unsigned char tmp = odd_parity[c];

( (tmp & 0x80) ? "1" : "0" );

( (tmp & 0x40) ? "1" : "0" );

( (tmp & 0x20) ? "1" : "0" );

( (tmp & 0x10) ? "1" : "0" );

( (tmp & 0x08) ? "1" : "0" );

( (tmp & 0x04) ? "1" : "0" );

( (tmp & 0x02) ? "1" : "0" );

( (tmp & 0x01) ? "1" : "0" );

void Des_String_To_Binary(const string& input, _b64& output)

{

string binary;

for (int i = 0; i < (); ++i ) {

}

_b64 tmp64(binary);

output = tmp64;

Des_Char_To_Binary(input[i], binary);

}

void Des_String_To_Key(const string& key, _vb48& subkey)

{

}

_b64 tmp64;

Des_String_To_Binary(key, tmp64);

Des_Key_Generate(tmp64, subkey);

void Des_Data_ExpPerm(const _b32& input, _b48& output)

{

Des_Permutation(input, output, dataexpperm_table, siz

eof(dataexpperm_table)/sizeof(int));

void Des_Data_IP(const _b64& input, _b64& output)

{

Des_Permutation(input, output, datainitperm_table, si

}

zeof(datainitperm_table)/sizeof(int));

void Des_Data_S(const _b6& input, _b4& output, int step)

{

bitset< 2 > tmp2;

_b4 tmp4;

tmp2[0] = input[5];

tmp2[1] = input[0];

tmp4[0] = input[1];

tmp4[1] = input[2];

}

tmp4[2] = input[3];

tmp4[3] = input[4];

_b8 t8(datasbox_table[step][_ulong()][_

ulong()]);

void Des_Data_P(const _b32& input, _b32& output)

{

Des_Permutation(input, output, datapperm_table, sizeo

void Des_Data_S(const _b48& input, _b32& output)

{

}

_b6 tmp6;

_b4 tmp4;

int i, j;

for (i = 0; i < 8; ++i) {

}

for (j = 6; j < 0; --j) {

}

Des_Data_S(tmp6, tmp4, i);

for (j = 0; j < 4; ++j) {

}

output[ 31 - (i << 2) - j] = tmp4[j];

tmp6[j] = input[ 47 - i*6 - j];

}

for (int i = 0; i < 4; ++i) {

}

output[i] = t8[i];

f(datapperm_table)/sizeof(int));

}

void Des_Data_F(_b64& input, const _b48& key)

{

}

_b32 l32, r32, tmp32, t32;

_b48 exp48;

int i;

for (i = 0; i < 32; ++i ) {

}

//cout << "r32** " << r32 << endl;

Des_Data_ExpPerm(r32, exp48);

//cout << "exp** " << exp48 << endl;

//cout << "key** " << key << endl;

exp48 ^= key;

//cout << "exp** " << exp48 << endl;

Des_Data_S(exp48, tmp32);

//cout << "tmp** " << tmp32 << endl;

Des_Data_P(tmp32, t32);

//cout << "t32** " << t32 << endl;

t32 ^= l32;

l32 = r32;

r32 = t32;

for (i = 0; i < 32; ++i ) {

}

input[i] = r32[i];

input[32+i] = l32[i];

r32[i] = input[i];

l32[i] = input[32+i];

void Des_data_FP(const _b64& input, _b64& output)

{

Des_Permutation(input, output, datafp_table, sizeof(d

atafp_table)/sizeof(int));

}

int Des_encode_64bit(const _vb48& key, const _b64 &data, _b64

&output)

utput)

Des_String_To_Key(key, subkey);

{

_vb48 subkey, decodekey;

_b64 data64, tmp64;

}

int Des_encode(const string& key, const string& data, _b64 &o

Des_Data_IP(data, tmp64);

for (int i = 0; i < 16; ++i) {

}

Des_data_FP(tmp64, output);

return 0;

//cout << " " << tmp64 << endl;

{

_b64 tmp64;

Des_Data_F(tmp64, key[i]);

//cout << " " << tmp64 << endl;

Des_encode_64bit(subkey, data64, output);

//cout << "code: " << output << endl;

//cout << "data: " << data64 << endl;

Des_String_To_Binary(data, data64);

for (int i = 0; i < 16; ++i) {

}

_back(subkey[ 15-i ]);

Des_encode_64bit(decodekey, output, tmp64);

//cout << "reco: " << tmp64 << endl;

if (tmp64 == data64) {

cout << "Congratulation.

$$$$$$$$$$$$$$$$$$$$$$$" << endl;

endl;

utput)

{

}

return 0;

}

int Des_decode(const string& key, const string& data, _b64 &o

return 0;

}

}else {

cout << "Error. **************************" <<

}

namespace gy {

/* Mode: true for encode, false for decode */

int Des(const string& key, const string& data, _b64 &output,

bool Mode)

{

}

void Run_Des(void)

{

int select = 0;

string data, key;

cout << "1. encode;" << endl << "2. decode;" << endl

if (Mode) {

return Des_encode(key, data, output);

}else {

}

return Des_decode(key, data, output);

<< "Your choise: ";

_b64 output;

cin >> select;

cout << endl << "Please input the data: ";

cin >> data;

cout << endl << "Please input the key: ";

cin >> key;

}

}

if (select == 1) {

Des(key, data, output, true);

}else {

}

Des(key, data, output, false);