3des.cpp

经典的加密解密程序

//3DES加密解密算法
#include <iostream>
#include <cstdlib>
#include <cstring>
#include <memory.h>
#include <stdio.h>
using namespace std;
typedef bool
(*PSubKey)[16][48];

// 初始置换
const static char Table_IP[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
};

// 末置换
const static char Table_InverseIP[64] =
{
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
};

// 扩展置换
static const char Table_E[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
};

// 密钥初始置换
const static char Table_PC1[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
};

// 左移运算
const static char Table_Moveleft[16] =
{
1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1
};

// 密钥压缩置换
const static char Table_PC2[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
};

// S盒
const static char Box_S[8][4][16] =
{
// S1
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,
// S2
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,
// S3
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,
// S4
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,
// S5
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,
// S6
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,
// S7
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,
// S8
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
};

// P盒置换
const static char Table_P[32] =
{
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
};

static bool SubKey[2][16][48];//两个密钥的16轮子密钥
static char Tmp[256], deskey[16];

#define ENCRYPT 0
#define DECRYPT 1

//通用置换函数
void Transform(bool *Out, bool *In, const char *Table, int len)
{
for(int i = 0; i < len; ++ i)
Tmp[i] = In[ Table[i] - 1 ];
memcpy(Out, Tmp, len);
}

//异或运算
void Xor(bool *InA, const bool *InB, int len)
{
for(int i = 0; i < len; ++ i)
InA[i] ^= InB[i];
}

//循环左移
void MoveLeft(bool *In, int len, int loop)
{
memcpy(Tmp, In, loop);
memcpy(In, In + loop, len - loop);
memcpy(In + len - loop, Tmp, loop);
}

//字节转换成位
void Byte2Bit(bool *Out, const char *In, int bits)
{
for(int i = 0; i < bits; ++ i)
Out[i] = (In[i >> 3] >> (i & 7)) & 1;
}

//位转换字节
void Bit2Byte(char *Out, const bool *In, int bits)
{
memset(Out, 0, bits >> 3);
for(int i = 0; i < bits; ++ i)
Out[i >> 3] |= In[i] << (i & 7);
}

//S 盒置换
void funS(bool Out[32], const bool In[48])
{
for(char i = 0, j, k; i < 8; ++ i, In += 6, Out += 4)
{
j = (In[0] << 1) + In[5];
k = (In[1] << 3) + (In[2] << 2) + (In[3] << 1) + In[4];
Byte2Bit(Out, &Box_S[i][j][k], 4);
}
}

//F 函数
void funF(bool In[32], const bool Ki[48])
{
static bool MR[48];
Transform(MR, In, Table_E, 48);
Xor(MR, Ki, 48);
funS(In, MR);
Transform(In, In, Table_P, 32);
}

//生成子密钥
void MakeSubKey(PSubKey pSubKey, const char Key[8])
{
static bool K[64], *KL = &K[0], *KR = &K[28];
Byte2Bit(K, Key, 64);
Transform(K, K, Table_PC1, 56);
for(int i = 0; i < 16; ++ i)
{
MoveLeft(KL, 28, Table_Moveleft[i]);
MoveLeft(KR, 28, Table_Moveleft[i]);
Transform((*pSubKey)[i], K, Table_PC2, 48);
}
}

//生成密钥
void MakeKey(const char* Key, int len)
{
memset(deskey, 0, 16);
memcpy(deskey, Key, len > 16 ? 16 : len);
MakeSubKey(&SubKey[1], &deskey[8]);
}

//一重DES加/解密
void DES(char Out[8], char In[8], const PSubKey pSubKey, bool Type)
{
static bool M[64], tmp[32], *Li = &M[0], *Ri = &M[32];
Byte2Bit(M, In, 64);
Transform(M, M, Table_IP, 64);
if( Type == ENCRYPT ){ //加密

for(int i = 0; i < 16; ++ i)
{
memcpy(tmp, Ri, 32);
funF(Ri, (*pSubKey)[i]);
Xor(Ri, Li, 32);
memcpy(Li, tmp, 32);
}
}
else //解密
{
for(int i = 15; i >= 0; -- i)
{
memcpy(tmp, Li, 32);
funF(Li, (*pSubKey)[i]);
Xor(Li, Ri, 32);
memcpy(Ri, tmp, 32);
}
}
Transform(M, M, Table_InverseIP, 64);
Bit2Byte(Out, M, 64);
}

bool DoDES(char *Out, char *In, long datalen, const char *Key, int keylen, bool Type)
{
if( !( Out && In && Key && (datalen=(datalen+7)&0xfffffff8) ) )
return false;

MakeKey(Key, keylen);
// 3次DES 加密:加(key0)-解(key1)-加(key0) 解密:解(key0)-加(key1)-解(key0)
for(long i = 0, j = datalen >> 3; i < j; ++ i, Out += 8, In += 8)
{
DES(Out, In,  &SubKey[0], Type);
DES(Out, Out, &SubKey[1], !Type);
DES(Out, Out, &SubKey[0], Type);
}
return true;
}

int main(int argc,char *argv[])
{
int i;
char key[255];
char buf[255];
char str[255]="chinaren";;
char key1[15]="12345678";
char key2[8]="aaaaaaa";

memset(key, 0, sizeof(key));
for (i = 0; i < 8; i ++)
{
key[i] = key1[i];
key[i + 8] = key2[i];
}

memset(buf, 0, sizeof(buf));
strcpy(buf, str);
cout<<"\nBefore encrypting\n";
cout<<buf<<endl;

DoDES(buf, buf, sizeof(str), key, sizeof(key), ENCRYPT);
cout<<"\nAfter encrypting\n";
cout<<buf<<endl;
FILE *fp1;
fp1=fopen("c:\\3des.txt","wb");
fwrite(buf,sizeof(buf),1,fp1);
printf("%d",sizeof(buf));
DoDES(buf, buf, sizeof(str), key, sizeof(key), DECRYPT);
cout<<"\nAfter decrypting\n";
cout<<buf<<endl;
FILE *fp2;
fp2=fopen("c:\\3des2.txt","wb");
fwrite(buf,sizeof(buf),1,fp2);
printf("%d",sizeof(buf));
return 0;
}