📄 des.cpp
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// DES.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include "math.h"
struct Sbox
{
int element[64];
}S_box[8]={ {14, 0, 4,15,13, 7, 1, 4, 2,14,15, 2,11,13, 8, 1, //0
3,10,10, 6, 6,12,12,11, 5, 9, 9, 5, 0, 3, 7, 8,
4,15, 1,12,14, 8, 8, 2,13, 4, 6, 9, 2, 1,11, 7,
15, 5,12,11, 9, 3, 7,14, 3,10,10, 0, 5, 6, 0,13},
{15, 3, 1,13, 8, 4,14, 7, 6,15,11, 2, 3, 8, 4,14, //1
9,12, 7, 0, 2, 1,13,10,12, 6, 0, 9, 5,11,10, 5,
0,13,14, 8, 7,10,11, 1,10, 3, 4,15,13, 4, 1, 2,
5,11, 8, 6,12, 7, 6,12, 9, 0, 3, 5, 2,14,15, 9},
{10,13, 0, 7, 9, 0,14, 9, 6, 3, 3, 4,15, 6, 5,10, //2
1, 2,13, 8,12, 5, 7,14,11,12, 4,11, 2,15, 8, 1,
13, 1, 6,10, 4,13, 9, 0, 8, 6,15, 9, 3, 8, 0, 7,
11, 4, 1,15, 2,14,12, 3, 5,11,10, 5,14, 2, 7,12},
{ 7,13,13, 8,14,11, 3, 5, 0, 6, 6,15, 9, 0,10, 3, //3
1, 4, 2, 7, 8, 2, 5,12,11, 1,12,10, 4,14,15, 9,
10, 3, 6,15, 9, 0, 0, 6,12,10,11, 1, 7,13,13, 8,
15, 9, 1, 4, 3, 5,14,11, 5,12, 2, 7, 8, 2, 4,14},
{ 2,14,12,11, 4, 2, 1,12, 7, 4,10, 7,11,13, 6, 1, //4
8, 5, 5, 0, 3,15,15,10,13, 3, 0, 9,14, 8, 9, 6,
4,11, 2, 8, 1,12,11, 7,10, 1,13,14, 7, 2, 8,13,
15, 6, 9,15,12, 0, 5, 9, 6,10, 3, 4, 0, 5,14, 3},
{12,10, 1,15,10, 4,15, 2, 9, 7, 2,12, 6, 9, 8, 5, //5
0, 6,13, 1, 3,13, 4,14,14, 0, 7,11, 5, 3,11, 8,
9, 4,14, 3,15, 2, 5,12, 2, 9, 8, 5,12,15, 3,10,
7,11, 0,14, 4, 1,10, 7, 1, 6,13, 0,11, 8, 6,13},
{ 4,13,11, 0, 2,11,14, 7,15, 4, 0, 9, 8, 1,13,10, // 6
3,14,12, 3, 9, 5, 7,12, 5, 2,10,15, 6, 8, 1, 6,
1, 6, 4,11,11,13,13, 8,12, 1, 3, 4, 7,10,14, 7,
10, 9,15, 5, 6, 0, 8,15, 0,14, 5, 2, 9, 3, 2,12},
{13, 1, 2,15, 8,13, 4, 8, 6,10,15, 3,11, 7, 1, 4, //7
10,12, 9, 5, 3, 6,14,11, 5, 0, 0,14,12, 9, 7, 2,
7, 2,11, 1, 4,14, 1, 7, 9, 4,12,10,14, 8, 2,13,
0,15, 6,12,10, 9,13, 0,15, 3, 3, 5, 5, 6, 8,11}};
////////////////////////////////////////////////////////////////////////////////////////////
/* 获取密钥 */
/*--------------------------------------------------*/
//从Key.txt中获取64位的密钥存pKey指向的数组
void GetKey( char *pKey )
{
struct Key8bit
{
unsigned a: 4; //注意ab不能互换
unsigned b: 4;
};
union
{
struct Key8bit Keyc;
char c;
}union1;
int i;
FILE *fp;
char tempc1,tempc2;
fp=fopen("Key.txt","rb");
for( i=0 ; i<8 ; i++ )
{
tempc1=fgetc(fp);
if(tempc1>='0' && tempc1<='9')
{
union1.Keyc.b=tempc1-48;
}
else if(tempc1>='a' && tempc1<='f')
{
union1.Keyc.b=tempc1-87;
}
else
{
union1.Keyc.b=tempc1-55;
}
tempc2=fgetc(fp);
if(tempc2>='0' && tempc2<='9')
{
union1.Keyc.a=tempc2-48;
}
else if(tempc1>='a' && tempc1<='f')
{
union1.Keyc.a=tempc2-87;
}
else
{
union1.Keyc.a=tempc2-55;
}
*(pKey+i)=union1.c;
}
fclose(fp);
}
/* 获取比特值 */
/*--------------------------------------------------*/
//pKey 指针指向数组
//i 表示要获取的第几比特位的值
//返回int型 1 或 0
int GetBitValue(char *pch , int i )
{
int flag;
struct Byte
{
unsigned bit7: 1;
unsigned bit6: 1;
unsigned bit5: 1;
unsigned bit4: 1;
unsigned bit3: 1;
unsigned bit2: 1;
unsigned bit1: 1;
unsigned bit0: 1;
};
union
{
struct Byte OneByte;
char Tempc;
}C;
C.Tempc = *(pch+(i/8));
switch( (i%8) )
{
case 0: {
if(C.OneByte.bit0 == 0)
flag = 0;
else flag = 1;
break;
}
case 1: {
if(C.OneByte.bit1 == 0)
flag = 0;
else flag = 1;
break;
}
case 2: {
if(C.OneByte.bit2 == 0)
flag = 0;
else flag = 1;
break;
}
case 3: {
if(C.OneByte.bit3 == 0)
flag = 0;
else flag = 1;
break;
}
case 4: {
if(C.OneByte.bit4 == 0)
flag = 0;
else flag = 1;
break;
}
case 5: {
if(C.OneByte.bit5 == 0)
flag = 0;
else flag = 1;
break;
}
case 6: {
if(C.OneByte.bit6 == 0)
flag = 0;
else flag = 1;
break;
}
case 7: {
if(C.OneByte.bit7 == 0)
flag = 0;
else flag = 1;
break;
}
}
return flag;
}
/* 设置比特位 */
/*--------------------------------------------------*/
//pKeyPC1 指针指向char型数组
//i 表示数组的第几比特位要设置
//flag int型1或0 表示第i位的比特位设置值
void SetBitValue(char *pKeyPC1 , int i , int flag)
{
struct Byte
{
unsigned bit7: 1;
unsigned bit6: 1;
unsigned bit5: 1;
unsigned bit4: 1;
unsigned bit3: 1;
unsigned bit2: 1;
unsigned bit1: 1;
unsigned bit0: 1;
};
union
{
struct Byte OneByte;
char Tempc;
}C;
C.Tempc = *(pKeyPC1+(i/8));
switch( (i%8) )
{
case 0: C.OneByte.bit0 = flag; break;
case 1: C.OneByte.bit1 = flag; break;
case 2: C.OneByte.bit2 = flag; break;
case 3: C.OneByte.bit3 = flag; break;
case 4: C.OneByte.bit4 = flag; break;
case 5: C.OneByte.bit5 = flag; break;
case 6: C.OneByte.bit6 = flag; break;
case 7: C.OneByte.bit7 = flag; break;
}
*(pKeyPC1+(i/8)) = C.Tempc;
}
/* 置换选择一 */
/*--------------------------------------------------*/
// 输入8字节的字符数组指针 pKey
// 输出到7字节的数组里 pKeyPC1
void PermutedChoice1( char *pKeyPC1 , char *pKey )
{
int i;
int PC_1[56]={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};
27,19,11, 3,60,52,44, 36,28,20,12, 4,61,53,
45,37,29,21,13, 5,62, 54,46,38,30,22,14, 6};
int flag;
for(i=0 ; i<56 ; i++)
{
flag = GetBitValue(pKey , PC_1[i] );
SetBitValue(pKeyPC1 , i , flag);
}
}
/* 循环移位 */
/*--------------------------------------------------*/
// 输入pC pD 移位数 LS
// 输出移位后的pC pD
void LeftShift(int LS, char *pKey)
{
int i;
int tempflag;
int flag;
for( ; LS>0 ; LS--)
{
tempflag = GetBitValue(pKey , 0);
for(i=0 ; i<27 ; i++)
{
flag = GetBitValue(pKey , i+1);
SetBitValue(pKey , i , flag);
}
SetBitValue(pKey , 27 , tempflag);
}
}
/* 置换选择二 */
/*--------------------------------------------------*/
void PermutedChoice2(char *pSubKey , int i , char *pKeyC , char *pKeyD)
{
int indexPC2[48]={ 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};
int m;
int flag;
for(m=0 ; m<48 ; m++)
{
if(indexPC2[m] < 28)
{
flag = GetBitValue(pKeyC , indexPC2[m]);
}
else
{
flag = GetBitValue(pKeyD , indexPC2[m]-28);
}
SetBitValue(pSubKey , i*48+m , flag);
}
}
/* 产生16子密钥 */
/*--------------------------------------------------*/
// 输入pC pD
// 输出16个子密钥
void ProcessSubkey(char *pSubKey , char *pKeyC , char *pKeyD)
{
int LS[16] = {1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1}; //循环左移
int i;
for(i=0 ; i<16 ; i++)
{
LeftShift(LS[i] , pKeyC);
LeftShift(LS[i] , pKeyD);
PermutedChoice2(pSubKey , i , pKeyC , pKeyD);
}
}
/*--------------分割置换选择一后的密钥--------------*/
/*--------------------------------------------------*/
void SplitPermutedKey(char *pKeyC , char *pKeyD , char *pKeyPC1 )
{
int i;
int j;
int flag;
for(i=0 ; i<28 ; i++)
{
flag = GetBitValue(pKeyPC1 , i );
SetBitValue(pKeyC , i , flag);
}
for(j=0 ; i<56 ; i++,j++)
{
flag = GetBitValue(pKeyPC1 , i);
SetBitValue(pKeyD , j , flag);
}
}
/* 获取待加密的数据 */
/*--------------------------------------------------*/
void GetData( char *pData )
{
*(pData+0)='l';
*(pData+1)='e';
*(pData+2)='a';
*(pData+3)='r';
*(pData+4)='n';
*(pData+5)='i';
*(pData+6)='n';
*(pData+7)='g';
/* *(pData+0)=86;
*(pData+1)=247;
*(pData+2)=29;
*(pData+3)=246;
*(pData+4)=182;
*(pData+5)=9;
*(pData+6)=234;
*(pData+7)=165;*/
}
/* 明文的初始置换IP */
/*--------------------------------------------------*/
void InitialPermutation( char *pData )
{
int indexIP[64]={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,
56,48,40,32,24,16, 8, 0,58,50,42,34,26,18,10, 2,
60,52,44,36,28,20,12, 4,62,54,46,38,30,22,14, 6};
int m;
int flag;
char Tempc[8];
for(m=0 ; m<64 ;m++)
{
flag = GetBitValue(pData , indexIP[m]);
SetBitValue(Tempc , m , flag);
}
for(m=0 ; m<64 ;m++)
{
flag = GetBitValue(Tempc , m);
SetBitValue(pData , m , flag);
}
}
/* E扩展 */
/*--------------------------------------------------*/
//pR 为4字节32比特位的字符数组的指针
//pER 为E扩展后6字节48比特位的字符数组指针
void ExpansionE(char *pER , char *pR)
{
int indexE[48]={31, 0, 1, 2, 3, 4, 3, 4, 5, 6, 7, 8,
7, 8, 9,10,11,12,11,12,13,14,15,16,
15,16,17,18,19,20,19,20,21,22,23,24,
23,24,25,26,27,28,27,28,29,30,31, 0};
int m;
int flag;
for(m=0 ; m<48 ; m++)
{
flag = GetBitValue(pR , indexE[m]);
SetBitValue(pER , m , flag);
}
}
/* 置换P */
/*--------------------------------------------------*/
void PermutationP( char *pR )
{
int indexP[32]={15, 6,19,20,28,11,27,16,
0,14,22,25, 4,17,30, 9,
1, 7,23,13,31,26, 2, 8,
18,12,29, 5,21,10, 3,24};
int m;
int flag;
char Tempc[4];
for(m=0 ; m<32 ;m++)
{
flag = GetBitValue(pR , indexP[m]);
SetBitValue(Tempc , m , flag);
}
for(m=0 ; m<32 ;m++)
{
flag = GetBitValue(Tempc , m);
SetBitValue(pR , m , flag);
}
}
/* 进入S_boxes */
/*--------------------------------------------------*/
void SboxFunction(char *pR , char *pER)
{
int i,k;
int value4,value6;
int flag;
for(i=0 ; i<8 ; i++)
{
value6 = 0;
for(k=0 ; k<6 ; k++)
{
flag = GetBitValue(pER , i*6+k);
if(flag == 1)
{
value6 = value6 + pow(2 , 6-k-1);
}
}
value4 = S_box[i].element[value6];
for(k=0 ; k<4 ; k++)
{
if(value4 >= pow(2 , 4-k-1))
{
flag = 1;
value4 = value4-pow(2 , 4-k-1);
SetBitValue(pR , i*4+k ,flag);
}
else
{
flag = 0;
SetBitValue(pR , i*4+k ,flag);
}
}
}
}
/* 轮函数 */
/*--------------------------------------------------*/
void FFunction( char *pR , char *pSubKey , int i)
{
char ER[6];
int j;
ExpansionE(ER , pR);
for(j=0 ; j<6 ; j++)
{
// ER[j] = ER[j] ^ (*(pSubKey+6*(16-1-i)+j));
ER[j] = ER[j] ^ (*(pSubKey+6*(i)+j));
}
SboxFunction( pR , ER );
PermutationP( pR );
}
/* 分割明文数据 */
/*--------------------------------------------------*/
// 输入64位明文
// 输出各32位的明文
void SplitData(char *pL , char *pR , char *pData)
{
int m , n;
for(m=0 ; m<4 ; m++)
{
*(pL+m) = *(pData+m);
}
for(n=0 ; n<4 ; n++,m++)
{
*(pR+n) = *(pData+m);
}
}
/* 合并两部分加密数据 */
/*--------------------------------------------------*/
void MergeEncryptedData(char *pEncryptedData , char *pL , char *pR)
{
int m,n;
for(m=0 ; m<4 ; m++)
{
*(pEncryptedData+m) = *(pL+m);
}
for(n=0 ; n<4 ; n++,m++)
{
*(pEncryptedData+m) = *(pR+n);
}
}
/* 逆初始置换 */
/*--------------------------------------------------*/
void FinalPermutation( char *pEncryptedData )
{
int indexIP_1[64]={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, 9,49,17,57,25,32, 0,40, 8,48,16,56,24};
int m;
int flag;
char Tempc[8];
for(m=0 ; m<64 ; m++)
{
flag = GetBitValue(pEncryptedData , indexIP_1[m]);
SetBitValue(Tempc , m , flag);
}
for(m=0 ; m<64 ; m++)
{
flag = GetBitValue(Tempc , m);
SetBitValue(pEncryptedData , m , flag);
}
}
/*------------------主函数部分-------------------*/
int main(int argc, char* argv[])
{
char Key[8];
GetKey( Key );
Key[0] = 'c';
Key[1] = 'o';
Key[2] = 'm';
Key[3] = 'p';
Key[4] = 'u';
Key[5] = 't';
Key[6] = 'e';
Key[7] = 'r';
char KeyPC1[7];
PermutedChoice1( KeyPC1 , Key );
char KeyC[4]; //KeyC共有32比特位 其实只需要前28个比特位 后4比特位没有使用
char KeyD[4]; //KeyD共有32比特位 其实只需要前28个比特位 后4比特位没有使用
SplitPermutedKey(KeyC , KeyD , KeyPC1); //1.2.2 Split the permuted key into two halves.
char SubKey[6*16]; //16个子密钥 每个密钥有6个字节长 48比特位
ProcessSubkey(SubKey , KeyC , KeyD);
char Data[8];
GetData( Data );
InitialPermutation( Data );
char L[4],R[4];
SplitData(L , R , Data);
int i,j;
char TempL[4];
for(i=0 ; i<16 ; i++)
{
for(j=0 ; j<4 ; j++)
{
TempL[j] = L[j];
L[j] = R[j];
}
FFunction( R , SubKey , i);
for(j=0 ; j<4 ; j++)
{
R[j]=R[j]^TempL[j];
}
}
char EncryptedData[8];
MergeEncryptedData(EncryptedData , R , L);
FinalPermutation( EncryptedData );
printf("Game Over!\n");
return 0;
}
/*------------------DES加密代码到此结束------------------*/⌨️ 快捷键说明
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