📄 des.cpp
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/*
* DES加解密算法-演示程序
* 作者：谢振哲(XieZhenZhe)
* 原创代码 @ 2009.03
*/
#include<iostream>
#include<string>
#include<bitset>
#include<time.h>
using namespace std;
#define BYTE unsigned char
class CDES
{
public:
bool DesEnter(const BYTE *input, BYTE *output, BYTE *key, int datalen, int mode);
private:
//初始换位表IP
static int ip[64];
//逆初始换位表IP_1
static int ip_1[64];
//16组子密钥
BYTE nkey[16][6];
//缩小换位表1
static int pc_1[56];
//缩小换位表2
static int pc_2[48];
//16轮密钥移位次数
static int MoveBit[16];
//放大换位表
static int e[48];
//P置换
static int p[32];
//S盒置换表
static BYTE s[8][4][16];
bool chkKey(BYTE *key);
void BinToByte(BYTE in[8], BYTE out[64], int len);
void ByteToBin(BYTE in[64], BYTE out[8], int len);
//加密函数
void Des_En(BYTE *output);
//加密函数
void Des_De(BYTE *output);
//最后一个分组补全64bit
void AddTo64bit(int datalen, BYTE *output);
//初始IP变换
void IPRound(BYTE *output);
//初始IP逆变换
void IPRound_1(BYTE *output);
//生成子密钥
void getRoundKey(BYTE *key);
//密钥转换选择PC_1
void KeyPC_1(BYTE *key, BYTE *out);
//密钥转换选择PC_2
void KeyPC_2(int S, BYTE *L, BYTE *R, BYTE *out);
//扩展转换E
void Expand(BYTE *in, BYTE *out);
//S盒替换及P盒置换
void SPReplace(BYTE *in, BYTE *out);
};
//初始换位表IP
int CDES::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
};
//逆初始换位表IP_1
int CDES::ip_1[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
};
//缩小换位表1
int CDES::pc_1[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
};
//缩小换位表2
int CDES::pc_2[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
};
//放大换位表
int CDES::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
};
//P置换
int CDES::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
};
//S盒
BYTE CDES::s[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
}
};
//16次循环左移对应的左移位数
int CDES::MoveBit[16] = {1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1};
void CDES::ByteToBin(BYTE in[], BYTE out[], int len)
{
int i;
for(i=0;i<len;i++)
{
out[i] = (in[i << 3] << 7) + (in[(i << 3) + 1] << 6) +
(in[(i << 3) + 2] << 5) + (in[(i << 3) + 3] << 4) +
(in[(i << 3) + 4] << 3) + (in[(i << 3) + 5] << 2) +
(in[(i << 3) + 6] << 1) + in[(i << 3) + 7];
}
}
void CDES::BinToByte(BYTE in[], BYTE out[], int len)
{
int i,j;
for(i=0;i<len;i++)
for(j=0;j<8;j++)
out[(i<<3)+j] = (in[i]>>(7-j)) & 0x01;
}
/*
* DesEnter 入口函数
* input 输入字节头指针
* output 输出字节头指针
* key 64bit密钥
* datalen 数据长度（单位字节，解密时须为8的倍数）
* mode 0加密，1解密，2验证密钥，3生成密钥
* 返回值：true成功，false失败
*/
bool CDES::DesEnter(const BYTE *input, BYTE *output, BYTE *key, int datalen, int mode)
{
//检验基本参数是否正确
if(((mode==1 || mode==2) && (input==0 || output==0 || key==0 || datalen<=0 )) || mode<0 || mode>3 || mode==1 && datalen%8!=0) return false;
//mode==0 加密
if(mode==0)
{
//if(!chkKey(key)) return false;
int i;
for(i=0;i<datalen;i++)
output[i]=input[i];
getRoundKey(key);
AddTo64bit(datalen, output);
datalen=datalen/8*8+8;
for(i=0;i<datalen;i+=8)
{
Des_En(output+i);
}
return true;
}
else if(mode==1) //解密
{
//if(!chkKey(key)) return false;
int i;
for(i=0;i<datalen;i++)
output[i]=input[i];
getRoundKey(key);
for(i=0;i<datalen;i+=8)
Des_De(output+i);
return true;
}
else if(mode==2)
{
if(!chkKey(key)) return false;
else return true;
}
else if(mode==3)
{
int i;
srand((unsigned int)time(NULL));
BYTE newkey[64];
do
{
for(i=0;i<64;i++)
newkey[i]=rand()%2;
}while(!chkKey(newkey));
ByteToBin(newkey,output,8);
return true;
}
else return false;
}
/*
* chkKey 检验密钥正确性
* key 64bit密钥
* 返回值：true 正确密钥，false 错误密钥
*/
bool CDES::chkKey(unsigned char *key)
{
int i;
for(i=0;i<8;i++)
{
bitset<8> OneKeyByte(key[i]);
if(OneKeyByte.count()%2==0) return false;
}
return true;
}
/*
* Des_En DES加密函数
* output 输出字节流
*/
void CDES::Des_En(unsigned char output[8])
{
//IP
IPRound(output);
BYTE L[17][4];
BYTE R[17][4];
BYTE tmp_after_E[6];
BYTE tmp_after_sp[4];
int i,j;
//L0,R0
for(i=0;i<4;i++)
{
L[0][i]=output[i];
R[0][i]=output[i+4];
}
//16轮迭代
for(i=1;i<=16;i++)
{
for(j=0;j<4;j++)
L[i][j]=R[i-1][j];
//E扩展
Expand(R[i-1],tmp_after_E);
//异或本轮子密钥
for(j=0;j<6;j++)
{
tmp_after_E[j]^=nkey[i-1][j];
}
SPReplace(tmp_after_E,tmp_after_sp);
for(j=0;j<4;j++)
R[i][j]=L[i-1][j]^tmp_after_sp[j];
}
//合成一个串
for(i=0;i<4;i++)
{
output[i]=R[16][i];
output[i+4]=L[16][i];
}
//IP_1
IPRound_1(output);
}
/*
* Des_De DES解密函数
* output 输出字节流
*/
void CDES::Des_De(unsigned char output[8])
{
//IP
IPRound(output);
BYTE L[17][4];
BYTE R[17][4];
BYTE tmp_after_E[6];
BYTE tmp_after_sp[4];
int i,j;
//L0,R0
for(i=0;i<4;i++)
{
L[16][i]=output[i];
R[16][i]=output[i+4];
}
//16轮迭代
for(i=15;i>=0;i--)
{
for(j=0;j<4;j++)
L[i][j]=R[i+1][j];
//E扩展
Expand(R[i+1],tmp_after_E);
//异或本轮子密钥
for(j=0;j<6;j++)
{
tmp_after_E[j]^=nkey[i][j];
}
SPReplace(tmp_after_E,tmp_after_sp);
for(j=0;j<4;j++)
R[i][j]=L[i+1][j]^tmp_after_sp[j];
}
//合成一个串
for(i=0;i<4;i++)
{
output[i]=R[0][i];
output[i+4]=L[0][i];
}
//IP_1
IPRound_1(output);
}
/*
* AdedTo64bit 将输入流复制到输出流，并补全最后一组为64bit
* datalen 数据长度（字节）
* input 输入字节流
* output 输出字节流
*/
void CDES::AddTo64bit(int datalen, unsigned char *output)
{
int i;
//不足64bit补全
if(datalen%8)
{
for(i=datalen;i<(datalen/8)*8+8;i++)
output[i]=0x08-(datalen%8);
}
else
{
for(i=datalen;i<datalen+8;i++)
output[i]=0x08;
}
}
/*
* IPRound 初始IP变换
* output 变换内容
*/
void CDES::IPRound(unsigned char *output)
{
BYTE tmp_old_byte[64];
BYTE tmp_new_byte[64];
int i;
BinToByte(output,tmp_old_byte,8);
for(i=0;i<64;i++)
{
tmp_new_byte[i]=tmp_old_byte[ip[i]-1];
}
ByteToBin(tmp_new_byte,output,8);
}
/*
* IPRound_1 初始IP逆变换
* output 变换内容
*/
void CDES::IPRound_1(unsigned char *output)
{
BYTE tmp_old_byte[64];
BYTE tmp_new_byte[64];
int i;
BinToByte(output,tmp_old_byte,8);
for(i=0;i<64;i++)
{
tmp_new_byte[i]=tmp_old_byte[ip_1[i]-1];
}
ByteToBin(tmp_new_byte,output,8);
}
void CDES::getRoundKey(unsigned char *key)
{
BYTE L[56]; //实际长度28,复制一倍
BYTE R[56];
int LS,RS; //L移位次数，R移位次数
BYTE tmp_after_pc_1[56];
//PC_1
KeyPC_1(key,tmp_after_pc_1);
//构造L0,R0
int i;
for(i=0;i<28;i++)
{
L[i+28]=L[i]=tmp_after_pc_1[i];
R[i+28]=R[i]=tmp_after_pc_1[i+28];
}
//初始置0
LS=RS=0;
//16轮变换
for(i=0;i<16;i++)
{
//换位
LS+=MoveBit[i];
RS+=MoveBit[i];
KeyPC_2(LS,L,R,nkey[i]);
}
}
/*
* KeyPC_1 密钥转换选择PC_1
* key 输入密钥64bit
* out 输出密钥56bit,Byte表示
*/
void CDES::KeyPC_1(BYTE key[8], BYTE out[56])
{
BYTE tmp_old_byte[64];
BinToByte(key,tmp_old_byte,8);
int i;
for(i=0;i<56;i++)
{
out[i]=tmp_old_byte[pc_1[i]-1];
}
}
/*
* KeyPC_2 密钥转换选择PC_2
* S 移位次数
* L 左28位
* R 右28位
* out 输出48位bit
*/
void CDES::KeyPC_2(int S, unsigned char *L, unsigned char *R, unsigned char out[6])
{
int i;
BYTE tmp_after_pc_2[48];
for(i=0;i<48;i++)
{
if(pc_2[i]>28)
tmp_after_pc_2[i]=R[pc_2[i]-28-1+S];
else
tmp_after_pc_2[i]=L[pc_2[i]-1+S];
}
ByteToBin(tmp_after_pc_2,out,6);
}
/*
* Expand 扩展转换E
* in 输入32bit
* out 输出48bit
*/
void CDES::Expand(BYTE *in, BYTE *out)
{
BYTE tmp_before_E[32];
BYTE tmp_after_E[48];
BinToByte(in,tmp_before_E,4);
int i;
for(i=0;i<48;i++)
{
tmp_after_E[i]=tmp_before_E[e[i]-1];
}
ByteToBin(tmp_after_E,out,6);
}
void CDES::SPReplace(unsigned char in[6], unsigned char out[4])
{
BYTE tmp_before_replace[48];
BYTE tmp_sout_bit[8];
BYTE tmp_before_p[32];
BYTE tmp_after_p[32];
BinToByte(in,tmp_before_replace,6);
int i,row,col;
for(i=0;i<8;i++)
{
//0、5位为row，1、2、3、4位为col
row=(tmp_before_replace[i*6]<<1)+(tmp_before_replace[i*6+5]);
col=(tmp_before_replace[i*6+1]<<3)+(tmp_before_replace[i*6+2]<<2)+(tmp_before_replace[i*6+3]<<1)+(tmp_before_replace[i*6+4]);
tmp_sout_bit[i]=s[i][row][col];
}
tmp_sout_bit[0]=(tmp_sout_bit[0]<<4)+tmp_sout_bit[1];
tmp_sout_bit[1]=(tmp_sout_bit[2]<<4)+tmp_sout_bit[3];
tmp_sout_bit[2]=(tmp_sout_bit[4]<<4)+tmp_sout_bit[5];
tmp_sout_bit[3]=(tmp_sout_bit[6]<<4)+tmp_sout_bit[7];
BinToByte(tmp_sout_bit,tmp_before_p,4);
for(i=0;i<32;i++)
{
tmp_after_p[i]=tmp_before_p[p[i]-1];
}
ByteToBin(tmp_after_p,out,4);
}
void about()
{
system("CLS");
printf("************************************* ZZ\n ╭︿︿︿╮ ZZ\n");
printf(" Copyright (C) 谢振哲 @2009.03 {/ ︿︿ /} z\n");
printf(" DES加解密算法-演示程序 ( (oo) )\n ︶︶︶ \n");
printf("*************************************\n\n\n");
}
int main()
{
char input_key[20],output_cipher[20];
int i;
BYTE key[10],plain[20],cipher[20],decode[20];
CDES des;
loop:
about();
memset(input_key,0,sizeof(input_key));
memset(output_cipher,0,sizeof(output_cipher));
memset(key,0,sizeof(key));
memset(plain,0,sizeof(plain));
memset(cipher,0,sizeof(cipher));
memset(decode,0,sizeof(decode));
printf("Input Key: ");
for(i=0;i<8;i++)
scanf("%2X",&key[i]);
printf("Input PlainText: ");
scanf(" %s",plain);
printf("CipherText: ");
des.DesEnter(plain,cipher,key,8,0);
for(i=0;i<8;i++)
printf("%02X",cipher[i]);
printf("\n");
printf("Decryption: ");
des.DesEnter(cipher,decode,key,8,1);
printf("%s\n",decode);
printf("\n继续输入吗？[y继续]");
scanf(" %s",plain);
if(plain[0]=='y') goto loop;
return 0;
}
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