DES加密算法与解密带流程图.doc

一、DES加密及解密算法程序源代码：

#include <iostream>
using namespace std;
const static char IP_Table[] = { //IP_Table置换
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 static char Final_Table[] = { //最终置换
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
};
const static char S_Box[8][64] = { //s_box
/* 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}
};
const static char Rar_Table[] = { //压缩置换
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 static char Exp_Table[] = { //扩展置换
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 static char P_Table[]={ //P置换
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
};
const static char KeyRar_Table[]={
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
};

//设置全局变量，16轮密钥
bool key[16][48]={{0}};

void ByteToBit(bool *Out,char *In,int bits) //字节到位转换函数
{
int i;
for(i=0;i<bits;i++)
Out[i]=(In[i/8]>>(i%8))&1;
}
void BitToByte(char *Out,bool *In,int bits) //位到字节转换函数
{
int i;
for(i=0;i<bits/8;i++)
Out[i]=0;
for(i=0;i<bits;i++)
Out[i/8]|=In[i]<<(i%8);
}
void Xor(bool *InA,const bool *InB,int length) //按位异或
{
for(int i=0;i<length;i++)
InA[i]^=InB[i];
}
void keyfc(char *In) //密钥生成函数
{
int i,j=0,mov,k,m;
bool* key0 = new bool[56];
bool* keyin = new bool[64];
bool temp;

ByteToBit(keyin,In,64); //字节到位的转换
for(i=0;i<56;i++) //密钥压缩为56位
key0[i]=keyin[KeyRar_Table[i]-1];
for(i=0;i<16;i++) //16轮密钥产生
{
if(i==0||i==1||i==8||i==15)
mov=1;
else
mov=2;
for(k=0;k<mov;k++) //分左右两块循环左移
{
for(m=0;m<8;m++)
{
temp=key0[m*7];
for(j=m*7;j<m*7+7;j++)
key0[j]=key0[j+1];
key0[m*7+6]=temp;
}
temp=key0[0];
for(m=0;m<27;m++)
key0[m]=key0[m+1];
key0[27]=temp;
temp=key0[28];
for(m=28;m<55;m++)
key0[m]=key0[m+1];
key0[55]=temp;
}

for(j=0;j<48;j++) //压缩置换并储存
key[i][j]=key0[Rar_Table[j]-1];
}
delete[] key0;
delete[] keyin;
}

void DES(char Out[8],char In[8],bool Type)//加密核心程序,Type=0时加密，反之解密
{
bool* MW = new bool[64];
bool* tmp = new bool[32];
bool* PMW = new bool[64];
bool* kzmw = new bool[48];
bool* keytem = new bool[48];
bool* ss = new bool[32];

int hang,lie,i;
ByteToBit(PMW,In,64);
for(int j=0;j<64;j++)
{
MW[j]=PMW[IP_Table[j]-1]; //初始置换
}
bool *Li=&MW[0],*Ri=&MW[32];
for(i=0;i<48;i++) //右明文扩展置换
kzmw[i]=Ri[Exp_Table[i]-1];

if(Type==0) //DES加密过程
{
for(int lun=0;lun<16;lun++)
{
for(i=0;i<32;i++)
ss[i]=Ri[i];
for(i=0;i<48;i++) //右明文扩展置换
kzmw[i]=Ri[Exp_Table[i]-1];
for(i=0;i<48;i++)
keytem[i]=key[lun][i];
Xor(kzmw,keytem,48);
/*S盒置换*/
for(i=0;i<8;i++)
{
hang=kzmw[i*6]*2+kzmw[i*6+5];
lie =kzmw[i*6+1]*8+kzmw[i*6+2]*4+kzmw[i*6+3]*2+kzmw[i*6+4];
tmp[i*4+3]=S_Box[i][(hang+1)*16+lie]%2;
tmp[i*4+2]=(S_Box[i][(hang+1)*16+lie]/2)%2;
tmp[i*4+1]=(S_Box[i][(hang+1)*16+lie]/4)%2;
tmp[i*4]=(S_Box[i][(hang+1)*16+lie]/8)%2;
}

for(i=0;i<32;i++) //P置换
Ri[i]=tmp[P_Table[i]-1];
Xor(Ri,Li,32); //异或
for(i=0;i<32;i++) //交换左右明文
{
Li[i]=ss[i];
}
}
for(i=0;i<32;i++)
{
tmp[i]=Li[i];
Li[i]=Ri[i];
Ri[i]=tmp[i];
}
for(i=0;i<64;i++)
PMW[i]=MW[Final_Table[i]-1];
BitToByte(Out,PMW,64); //位到字节的转换
}
else //DES解密过程
{

for(int lun=15;lun>=0;lun--)
{
for(i=0;i<32;i++)
ss[i]=Ri[i];
for(i=0;i<48;i++) //右明文扩展置换
kzmw[i]=Ri[Exp_Table[i]-1];
for(i=0;i<48;i++)
keytem[i]=key[lun][i];
Xor(kzmw,keytem,48);
/*S盒置换*/
for(i=0;i<8;i++)
{
hang=kzmw[i*6]*2+kzmw[i*6+5];
lie =kzmw[i*6+1]*8+kzmw[i*6+2]*4+kzmw[i*6+3]*2+kzmw[i*6+4];
tmp[i*4+3]=S_Box[i][(hang+1)*16+lie]%2;
tmp[i*4+2]=(S_Box[i][(hang+1)*16+lie]/2)%2;
tmp[i*4+1]=(S_Box[i][(hang+1)*16+lie]/4)%2;
tmp[i*4]=(S_Box[i][(hang+1)*16+lie]/8)%2;
}

for(i=0;i<32;i++) //P置换
Ri[i]=tmp[P_Table[i]-1];
Xor(Ri,Li,32); //异或
for(i=0;i<32;i++) //交换左右明文
{
Li[i]=ss[i];
}

}
for(i=0;i<32;i++)
{
tmp[i]=Li[i];
Li[i]=Ri[i];
Ri[i]=tmp[i];
}
for(i=0;i<64;i++)
PMW[i]=MW[Final_Table[i]-1];
BitToByte(Out,PMW,64); //位到字节的转换
}

delete[] MW;
delete[] tmp;
delete[] PMW;
delete[] kzmw;
delete[] keytem;
delete[] ss;
}

bool RunDes(char *Out, char *In, int datalength, char *Key, bool Type) //加密运行函数，判断输入以及对输入文本8字节分割
{
if( !( Out && In && Key && (datalength=(datalength+7)&0xfffffff8) ) )
return false;
keyfc(Key);
for(int i=0,j=datalength%8; i<j; ++i,Out+=8,In+=8)
DES(Out, In, Type);
return true;
}

int main()
{
char* Ki = new char[8];
char Enter[]="This is the test of DES!";
char* Print = new char[200];
int len = sizeof(Enter);
int i_mf;

cout << "请输入密钥（8位）：" <<"\n";
for(i_mf=0;i_mf<8;i_mf++)
cin >> Ki[i_mf];
cout << "\n";
RunDes(Print,Enter,len,Ki,0);//加密

cout << "----加密前----" << "\n";
for(i_mf=0;i_mf<len;i_mf++)
cout << Enter[i_mf];
cout << "\n\n";

cout << "----加密后----" << "\n";
for(i_mf=0;i_mf<len;i_mf++)
cout<<Print[i_mf];
cout << "\n\n";

//此处进行不同密钥输入测试
cout << "请输入密钥（8位）：" <<"\n";
for(i_mf=0;i_mf<8;i_mf++)
cin >> Ki[i_mf];
cout << "\n";

RunDes(Enter,Print,len,Ki,1);//解密

cout << "----解密后----" << "\n";
for(i_mf=0;i_mf<len;i_mf++)
cout << Enter[i_mf];
cout << endl;

delete[] Ki;
delete[] Print;

return 0;
}

二、程序编译、运行结果图：

三、程序总体框架图：

四、程序实现流程图：