📄 des.cpp
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#include<stdio.h>
#include<math.h>
int ToBin(int bin[],char c)
{//将字符c转换成八位2进制数
int i = 0;
while(c)
{
bin[i] = c % 2;
c = c /2;
i++;
}
for(int j = i;j < 8;j++)
bin[j] = 0;
return 0;
}//ToBin
int ConvertToBin(int result[],char source[])
{//source数组转换为64bit存入result
int bin[8];
int k = 0;
for(int i = 0;i < 8;i++)
{
ToBin(bin,source[i]);
for(int j = 7;j >= 0;j--)
{
result[k] = bin[j];
k++;
}//for
}//for
return 0;
}//ConvertToBin
int ConvertToBinSK(int result[],char source[])
{//密文转换为2进制并添加奇偶校验位
int bin[8];
int k = 0;
for(int i = 0;i < 7;i++)
{
ToBin(bin,source[i]);
for(int j = 7;j >= 0;j--)
{
if((k+1)%8 == 0)
{
result[k++] = 0; //添加奇偶校验位
j++;
}
else
result[k++] = bin[j];
}//for j
}//for i
result[63] = 0;
return 0;
}//ConvertToBinSK
int ConvertToChar(int Word[],int result[])
{
int k = 0;
for(int i = 0;i < 64;i = i+8)
result[k++] = Word[i]*pow(2,7)+Word[i+1]*pow(2,6)+Word[i+2]*pow(2,5)+
Word[i+3]*pow(2,4)+Word[i+4]*pow(2,3)+Word[i+5]*pow(2,2)+
Word[i+6]*pow(2,1)+Word[i+7]*pow(2,0);
return 0;
}
int InitPermute(int result[],int source[],int IPA[])
{//初始置换
for(int i = 0;i < 64;i++)
result[i] = source[IPA[i]-1];
return 0;
}//InitPermute
int ExtendPermute(int result[],int source[],int EPA[])
{//扩展置换 32位扩展至48位
for(int i = 0;i < 48;i++)
result[i] = source[EPA[i]-1];
return 0;
}//ExtendPermute
int SecretKeyPermute(int result[],int source[],int SKPA[])
{//密钥去奇偶校验位
for(int i = 0;i < 56;i++)
result[i] = source[SKPA[i]];
return 0;
}//SecretKeyPermute
int ReducePermute(int result[],int source[],int RPA[])
{//压缩置换 56bits->48bits
for(int i = 0;i < 48;i++)
result[i] = source[RPA[i]];
return 0;
}//ReducePermute
int LeftShift(int source[],int n)
{//左移n位
int temp;
for(int i = 0;i < n;i++)
{
temp = source[0];
for(int k = 0;k < 27;k++)
source[k] = source[k+1];
source[k] = temp;
}
return 0;
}//LeftShift
int XOR(int a,int b)
{//a xor b
int c;
c = a + b;
if(c == 2)
c = 0;
return c;
}//XOR
int GetSecretKey(int SecretKeyA[][48],int SecretA[])
{//得到16个密匙 SecretA为密匙数组64bits
int ShiftQueue[] = {1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1}; //左移队列
int C[28],D[28];
int SKPA[] = {56,48,40,32,24,16,8,
0,57,49,41,33,25,17,
9,1,58,50,42,34,26,
18,10,2,59,51,43,35,
62,54,46,38,30,22,14,
6,61,53,45,37,29,21,
13,5,60,52,44,36,28,
20,12,4,27,19,11,3};//密钥去奇偶校验位数组
int RPA[] = {13,16,10,23,0,4,
2,27,14,5,20,9,
22,18,11,3,25,7,
15,6,26,19,12,1,
40,51,30,36,46,54,
29,39,50,44,32,47,
43,48,38,55,33,52,
45,41,49,35,28,31}; //压缩置换数组
int SK[56];
SecretKeyPermute(SK,SecretA,SKPA); //64bits->56bits
for(int i = 0;i < 28;i++)
{//密文数组分为C、D两个部分
C[i] = SK[i];
D[i] = SK[i+28];
}//for
for(int k = 0;k < 16;k++)
{//计算出16个密匙存入SecretKeyA
LeftShift(C,ShiftQueue[k]);
LeftShift(D,ShiftQueue[k]); //密匙左移ShiftQueue[k]
int temp[56];
for(int ti = 0;ti < 28;ti++)
{
temp[ti] = C[ti];
temp[ti+28] = D[ti];
}//for ti
int SecretTemp[48]; //暂存密匙数组
ReducePermute(SecretTemp,temp,RPA); //压缩置换 56bits->48bits
for(int si = 0;si < 48;si++)
SecretKeyA[k][si] = SecretTemp[si];
}//for k
return 0;
}//GetSecretKey
int SPermute(int source[],int result[])
{//S盒置换
int s1[16][4] = {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};
int s2[16][4] = {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};
int s3[16][4] = {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};
int s4[16][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};
int s5[16][4] = {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};
int s6[16][4] = {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};
int s7[16][4] = { 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};
int s8[16][4] = {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 temp[8];
int IA[8]; //S盒置换的行坐标
int JA[8]; //S盒置换的列坐标
int k = 0;
for(int i = 0;i < 48;i = i + 6)
IA[k++] = source[i]*2 + source[i+5];
k = 0;
for(int j = 1;j < 48;j = j + 6)
JA[k++] = source[j]*2*2*2 + source[j+1]*2*2 + source[j+2]*2 + source[j+3];
temp[0] = s1[IA[0]][JA[0]];
temp[1] = s2[IA[1]][JA[1]];
temp[2] = s3[IA[2]][JA[2]];
temp[3] = s4[IA[3]][JA[3]];
temp[4] = s5[IA[4]][JA[4]];
temp[5] = s6[IA[5]][JA[5]];
temp[6] = s7[IA[6]][JA[6]];
temp[7] = s8[IA[7]][JA[7]];
int bin[8];
int ri = 0;
for(int ti = 0;ti < 8;ti++)
{
ToBin(bin,temp[ti]);
for(int n = 3;n >= 0;n--)
result[ri++] = bin[n];
}
return 0;
}//SPermute
int Encrypt(char InPut[],int SecretKey[][48],int SecretWord[])
{//加密 InPut存储明文 SecretKey为16个密钥 SecretWord为输出的密文64bits
int ConvertTemp[64]; //明文64bits
int des[64];
int IPA[] = {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}; //初始置换数组
int EPA[] = {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}; //扩展置换数组
int PPA[] = {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};//P置换数组
ConvertToBin(ConvertTemp,InPut); //输入的明文转换成64bits
InitPermute(des,ConvertTemp,IPA);//明文初始置换
int R[32],L[32];
for(int RLi = 0;RLi < 32;RLi++)
{
L[RLi] = des[RLi];
R[RLi] = des[RLi+32];
}//明文经IP置换分成两个数组
int Eresult[48]; //扩展置换后存放的数组
int Sresult[32]; //S盒置换后存放的数组
int XorAF[48]; //存放第一次异或的结果
int XorAS[32]; //存放第二次异或的结果
int PPResult[32];//P置换后存放结果
for(int i = 0;i < 16;i++)
{//16轮加密
ExtendPermute(Eresult,R,EPA); //32bits->48bits
for(int xi = 0;xi < 48;xi++)
XorAF[xi] = XOR(Eresult[xi],SecretKey[i][xi]); //异或
SPermute(XorAF,Sresult); //S盒置换存入Sresult
for(int ppi = 0;ppi < 32;ppi++)
PPResult[ppi] = Sresult[PPA[ppi]-1]; //P置换
for(int li = 0;li < 32;li++)
XorAS[li] = XOR(L[li],PPResult[li]);
//下一轮的R和L数组
for(int k = 0;k < 32;k++)
L[k] = R[k];
for(int m = 0;m < 32;m++)
R[m] = XorAS[m];
}//for
int TempWord[64];
for(int n = 0;n < 32;n++)
{
TempWord[n] = R[n];
TempWord[n+32] = L[n];
}
int OIPA[] = {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,
36,4,44,12,52,20,60,38,
35,3,43,11,51,19,59,27,
34,2,42,10,50,18,58,26,
33,1,41, 9,49,17,57,25}; //逆初始置换数组
for(int swi = 0;swi < 64;swi++)
SecretWord[swi] = TempWord[OIPA[swi]-1]; //逆初始置换
return 0;
}//Encrypt
int Decryption(int SecretKey[][48],int SecretWord[],int Word[])
{//解密 SecretWord密文 word为解密后的原文
int des[64];
int IPA[] = {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}; //初始置换数组
int EPA[] = {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}; //扩展置换数组
int PPA[] = {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};//P置换数组
InitPermute(des,SecretWord,IPA);//密文初始置换
int R[32],L[32];
for(int RLi = 0;RLi < 32;RLi++)
{
L[RLi] = des[RLi];
R[RLi] = des[RLi+32];
}//明文经IP置换分成两个数组
int Eresult[48]; //扩展置换后存放的数组
int Sresult[32]; //S盒置换后存放的数组
int XorAF[48]; //存放第一次异或的结果
int XorAS[32]; //存放第二次异或的结果
int PPResult[32];//P置换后存放结果
for(int i = 15;i >= 0;i--)
{//16轮解密
ExtendPermute(Eresult,R,EPA); //32bits->48bits
for(int xi = 0;xi < 48;xi++)
XorAF[xi] = XOR(Eresult[xi],SecretKey[i][xi]); //异或
SPermute(XorAF,Sresult); //S盒置换存入Sresult
for(int ppi = 0;ppi < 32;ppi++)
PPResult[ppi] = Sresult[PPA[ppi]-1]; //P置换
for(int li = 0;li < 32;li++)
XorAS[li] = XOR(L[li],PPResult[li]);
//下一轮的R和L数组
for(int k = 0;k < 32;k++)
L[k] = R[k];
for(int m = 0;m < 32;m++)
R[m] = XorAS[m];
}//for
int TempWord[64];
for(int n = 0;n < 32;n++)
{
TempWord[n] = R[n];
TempWord[n+32] = L[n];
}
int OIPA[] = {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,
36,4,44,12,52,20,60,38,
35,3,43,11,51,19,59,27,
34,2,42,10,50,18,58,26,
33,1,41, 9,49,17,57,25}; //逆初始置换数组
for(int swi = 0;swi < 64;swi++)
Word[swi] = TempWord[OIPA[swi]-1]; //逆初始置换
return 0;
}//Decryption
void main()
{
char InPut[8];
printf("请输入明文:");
for(int i = 0;i < 8;i++)
InPut[i] = getchar(); //输入明文
getchar();
int ya[64];
ConvertToBin(ya,InPut);
for(int y = 0;y < 64;y++)
printf("%d",ya[y]);
printf("\n");
char SecretKey[7]; //输入的密匙
int SecretKeyA[16][48]; //16个密匙
int SecretA[64]; //密匙添加奇偶校验位转换成64bits数组
printf("请输入密匙:");
for(int ski = 0;ski < 7;ski++)
SecretKey[ski] = getchar();
ConvertToBinSK(SecretA,SecretKey); //密匙56bits->64bits
GetSecretKey(SecretKeyA,SecretA); //获得密匙
int SecretWord[64]; //密文数组
Encrypt(InPut,SecretKeyA,SecretWord);//加密
for(int sw = 0;sw < 64;sw++)
printf("%d",SecretWord[sw]);
printf("\n");
int Word[64];
Decryption(SecretKeyA,SecretWord,Word); //解密
for(int w = 0;w < 64;w++)
printf("%d",Word[w]);
printf("\n");
int result[8];
ConvertToChar(Word,result);
for(int re = 0;re < 8;re++)
printf("%c",result[re]);
printf("\n");
}
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