c++ 实现 DES 加密

该博客提供了用C/C++实现的DES加密解密函数。给出了加密函数bitset<64> DES(bitset<64> data,bitset<64> key,DESMODE::encrypt)和解密函数的使用示例,还详细介绍了实现细节,包括ip和逆ip变换、子密钥生成、f函数等文件的代码。

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自己写的,可能有bug,不过能用就行了。

你不想看实现细节就直接用函数

bitset<64> DES(bitset<64> data,bitset<64> key,DESMODE::encrypt) 加密

或者

bitset<64> DES(bitset<64> data,bitset<64> key,DESMODE::decrypt) 解密就行了

用法示例

#include <iostream>

#include"DES.hpp"

#include"subkeygen.hpp"

using namespace std;

int main()

{

bitset<64> data("0111000000000000000000000000000000000000000000000000000000000011");

bitset<64> key(4785148548);

cout << data << endl;

auto t1=DES(data, key,DESMODE::encrypt);

cout << t1 << endl;

auto t2 = DES(t1, key, DESMODE::decrypt);

cout << t2 << endl;

}

 

以下是实现的细节,你需要按以下顺序创建文件

文件 ip.hpp   ip和逆ip变换

#pragma once

#include<bitset>

using namespace std;

unsigned int IP[] =

{

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,

};

unsigned int IP_1[] =

{

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

};

//ip置换

bitset<64> fip(const bitset<64> &input)

{

bitset<64> output;

for (int i = 0; i < 64; i++)

{

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

}

return output;

}

//反向ip

bitset<64> fip_1(const bitset<64> &input)

{

bitset<64> output;

for (int i = 0; i < 64; i++)

{

output[i] = input[IP_1[i] - 1];

}

return output;

}

 

文件 subkeygen.hpp 生成子密钥

#pragma once

#include<bitset>

#include<vector>

using namespace std;

unsigned int SHIFT[] = { 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 };

unsigned int PC1[] =

{

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

};

unsigned int PC2[] =

{

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

};

//生成子密钥

vector<bitset<48>> subkeygen(const bitset<64> &input)

{

vector<bitset<48>> output;

bitset<48> output_val;

bitset<28> L;

bitset<28> R;

bitset<56> LR;

for (int i = 0; i < 56; i++)

LR[i] = input[PC1[i] - 1];

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

{

L[i] = LR[i];

R[i] = LR[i + 28];

}

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

{

L = (L << SHIFT[i]) | L >> (28 - SHIFT[i]);

R = (R << SHIFT[i]) | R >> (28 - SHIFT[i]);

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

{

LR[i] = L[i];

LR[i + 28] = R[i];

}

for (int i = 0; i < 48; i++)

output_val[i] = LR[PC2[i] - 1];

output.push_back(output_val);

}

return output;

}

 

文件 f.hpp  f函数

#pragma once

#include<bitset>

#include<array>

using namespace std;

unsigned int E[] =

{

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

};

unsigned int SBOXS[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, 10, 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

},

{

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

},

{

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

},

{

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

},

{

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,

},

{

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

},

{

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

}

};

int P[] = { 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 };

bitset<32> ff(const bitset<32> &data, const bitset<48> &key)

{

bitset<48> exdata;

bitset<32> cat;

bitset<32> output;

for (int i = 0; i < 48; i++)

{

exdata[i] = data[E[i] - 1];

}

exdata ^= key;

int p = 0;

int _p = 0;

array<bitset<6>, 8> boxarray;

//八个s盒子

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

{

//一个盒子输入六位

for (int j = 0; j < 6; j++)

{

(boxarray[i])[j] = exdata[p];

++p;

}

bitset<2> row;

int irow;

bitset<4> col;

bitset<4> out(0);

int icol;

row[0] = boxarray[i][0];

row[1] = boxarray[i][5];

irow = row.to_ulong();

col[0] = boxarray[i][1];

col[1] = boxarray[i][2];

col[2] = boxarray[i][3];

col[3] = boxarray[i][4];

icol = col.to_ulong();

out = SBOXS[i][irow][icol];

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

{

cat[_p] = out[i];

_p++;

}

}

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

{

output[i] = cat[P[i] - 1];

}

return output;

}

 

文件 DES.hpp   X_X

#pragma once

#include"ip.hpp"

#include"subkeygen.hpp"

#include"F.hpp"

#include<bitset>

using namespace std;

enum DESMODE

{

encrypt = 1,

decrypt = 2

};

bitset<64> DES(bitset<64> input, bitset<64> key,const int &mode)

{

auto keys = subkeygen(key);

fip(input);

bitset<32> L, R, t;

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

{

L[i] = input[i];

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

}

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

{

if (mode == 1)

{

L ^= ff(R, keys[i]);

}

else

{

L ^= ff(R, keys[15 - i ]);

}

if (i != 15)

{

t = L;

L = R;

R = t;

}

}

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

{

input[i] = L[i];

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

}

fip_1(input);

return input;

}

转载于:https://www.cnblogs.com/nuhaixianyu/p/10566135.html

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