📄 des.cpp
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// DES.cpp : 定义控制台应用程序的入口点。
//
#include "stdafx.h"
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
// DES.cpp: implementation of the DES class.
//
//////////////////////////////////////////////////////////////////////
//#include "DES.h"
#include <iostream>
#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif
//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////
DES::DES()
{
}
DES::~DES()
{
}
// initial permutation IP 初始置换
const static char IP_Table[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
};
// final permutation IP^-1 逆初始置换
const static char IPR_Table[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
};
//的F变 expansion operation matrix 扩展变换，属于右半部分换，变换后与48位密钥异或后进行S变换
static const char E_Table[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
};
// 32-bit permutation function P used on the output of the S-boxes S变换后进行P变换
const static char P_Table[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
};
// permuted choice table (key) 密钥的置换选择1
const static char PC1_Table[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,
//后面28位的操作
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
};
// permuted choice key (table) 密钥的置换选择2
const static char PC2_Table[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
};
// number left rotations of pc1 循环左移位表
const static char LOOP_Table[16] = {
1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1
};
// The (in)famous S-boxes S变换表，每一部分进6bit出4bit
const static char S_Box[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
};
//////////////////////////////////////////////////////////////////////////
typedef bool (*PSubKey)[16][48]; //由传进去的key经过变换生成
char str1[50],str2[50];
char *FILENAME1=str1,*FILENAME2=str2;
FILE *fp, *fp2;
char buffer[8];
//////////////////////////////////////////////////////////////////////////
static void SDES(char Out[8], char In[8], const PSubKey pSubKey, bool Type);//标准DES加/解密
static void SetKey(const char* Key, int len);// 设置密钥
static void SetSubKey(PSubKey pSubKey, const char Key[8]); // 设置子密钥
static void F_func(bool In[32], const bool Ki[48]);// f 函数
static void S_func(bool Out[32], const bool In[48]);// S 盒代替
static void Transform(bool *Out, bool *In, const char *Table, int len);// 变换
static void Xor(bool *InA, const bool *InB, int len);// 异或
static void RotateL(bool *In, int len, int loop);// 循环左移
static void ByteToBit(bool *Out, const char *In, int bits);// 字节组转换成位组
static void BitToByte(char *Out, const bool *In, int bits);// 位组转换成字节组
//////////////////////////////////////////////////////////////////////////
static bool SubKey[2][16][48];// 16圈子密钥 48位是经过置换后的密钥，2表示可以用来存放两组密钥（3次des要使用两组密钥）
static bool Is3DES;// 3次DES标志
static char Tmp[256], deskey[16];
//////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////
// Code starts from Line 130
//////////////////////////////////////////////////////////////////////////
void SetKey(const char* Key, int len) // 设置密钥
{
memset(deskey, 0, 16);
memcpy(deskey, Key, len>16?16:len);
SetSubKey(&SubKey[0], &deskey[0]); //&SubKey[0]用来存放1次DES算法的子密钥序列
Is3DES = len>8 ? (SetSubKey(&SubKey[1], &deskey[8]), true) : false; ////&SubKey[1]用来存放3次DES算法的第二个子密钥序列
}
void SDES(char Out[8], char In[8], const PSubKey pSubKey, bool Type) //标准DES加/解密
{
static bool M[64], tmp[32], *Li=&M[0], *Ri=&M[32];
ByteToBit(M, In, 64);
Transform(M, M, IP_Table, 64); //进行初始的IP置换
if( Type == ENCODE )
{
for(int i=0; i<16; i++)
{
memcpy(tmp, Ri, 32); //bool tmp[32]，暂时保存Ri,在后面将其给Li
F_func(Ri, (*pSubKey)[i]); //F变换，结果存到Ri
Xor(Ri, Li, 32);
memcpy(Li, tmp, 32);
}
}
else //解密过程，实际上就是将加密过程中的Ri和Li互换
{
for(int i=15; i>=0; i--)
{
memcpy(tmp, Li, 32);
F_func(Li, (*pSubKey)[i]);
Xor(Li, Ri, 32);
memcpy(Ri, tmp, 32);
}
}
//进行逆初始变换
Transform(M, M, IPR_Table, 64);
BitToByte(Out, M, 64);
}
void SetSubKey(PSubKey pSubKey, const char Key[8]) // 设置子密钥
{
static bool K[64], *KL=&K[0], *KR=&K[28];
ByteToBit(K, Key, 64);
Transform(K, K, PC1_Table, 56); //密钥的置换选择1，注意：64位密钥这里只用了前面的56位，此处认为奇偶校验位为最后的8位，并且在此被忽略
for(int i=0; i<16; i++)
{
RotateL(KL, 28, LOOP_Table[i]);
RotateL(KR, 28, LOOP_Table[i]);
Transform((*pSubKey)[i], K, PC2_Table, 48); //密钥的置换选择2 Transform(bool *Out, bool *In, const char *Table, int len)
}
}
void F_func(bool In[32], const bool Ki[48])
{
static bool MR[48];
Transform(MR, In, E_Table, 48); //对32位的加密内容的右半部分进行扩展变换
Xor(MR, Ki, 48); //结果和产生的48位子密钥进行异或运算,Ki就是pSubKey中的一个元素
S_func(In, MR); //进行S变换
Transform(In, In, P_Table, 32); //将结果进行P置换
}
void S_func(bool Out[32], const bool In[48])
{
for(char i=0,j,k; i<8; ++i,In+=6,Out+=4) //对输入进行分组,In和Out对应的都是指针地址，所以可以相加
{
j = (In[0]<<1) + In[5]; //组合成一个两位的二进制数来选择行
k = (In[1]<<3) + (In[2]<<2) + (In[3]<<1) + In[4]; ////组合成一个四位的二进制数来选择列
ByteToBit(Out, &S_Box[i][j][k], 4);
}
}
void Transform(bool *Out, bool *In, const char *Table, int len)
{
for(int i=0; i<len; i++)
Tmp[i] = In[ Table[i]-1 ]; //查表操作
memcpy(Out, Tmp, len); //保存查表结果
}
void Xor(bool *InA, const bool *InB, int len)
{
for(int i=0; i<len; i++)
InA[i] ^= InB[i];
}
void RotateL(bool *In, int len, int loop) //将In指针指向的数据进行左移
{
memcpy(Tmp, In, loop);
memcpy(In, In+loop, len-loop);
memcpy(In+len-loop, Tmp, loop);
}
void ByteToBit(bool *Out, const char *In, int bits)
{
for(int i=0; i<bits; i++)
Out[i] = (In[i>>3]>>(i&7)) & 1; //此处的算法比较难懂，待调试检验
}
void BitToByte(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); //此处的算法比较难懂，待调试检验
}
bool DESCODE(FILE *fp2, FILE *fp, long datalen, const char *Key, int keylen, bool Type) //这是主要函数，从这里开始执行算法调用
{
//if( !( Out && In && Key && (datalen=(datalen+7)&0xfffffff8) ) ) //？
//return false;
SetKey(Key, keylen); //Is3DES通过SetKey设置
if( !Is3DES )
{ // 1次DES
int tmp;
for(long i=0,j=datalen>>3; i<=j; i++){
memset(buffer,'\0',8);
tmp=fread(buffer,1,8,fp);
if(tmp>0){
SDES(buffer, buffer, &SubKey[0], Type);
if(fwrite(buffer,1,8,fp2)==0)printf("数据写入失败\n");
}
}
}
else
{ // 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++) //初始化j=datalen/8
{
int tmp;
memset(buffer,'\0',8);
tmp=fread(buffer,1,8,fp);
if(tmp>0){
SDES(buffer, buffer, &SubKey[0], Type);
SDES(buffer, buffer, &SubKey[1], !Type);
SDES(buffer, buffer, &SubKey[0], Type);
if(fwrite(buffer,1,8,fp2)==0)printf("数据写入失败\n");
}
}
}
return true;
}
int main(int argc, char* argv[])
{
int flag;
char key[16];
char *keytmp;
printf("请输入原文件名:\n");
scanf("%s",FILENAME1);
printf("请输入目标文件名:\n");
scanf("%s",FILENAME2);
printf("请输入密钥:\n");
scanf("%s",&key);
if ((fp= fopen(FILENAME1,"rb")) == NULL || (fp2 = fopen(FILENAME2,"wb"))==NULL)
{
printf("文件打开失败\n");
char awp;
scanf("%d",&awp);
return 0;
}
fseek(fp,0,SEEK_END); //将文件指针移到文件末尾
long filelen = ftell(fp); //获取指针当前位置到文件开头的偏移量
rewind(fp); //将文件指针移到文件开头
keytmp=key;
int keylen = strlen(keytmp);
printf("请选择操作种类，0表示加密，1表示解密：");
scanf("%d",&flag);
switch (flag)
{
case 0:
DESCODE(fp2,fp,filelen,key,keylen,0);
break;
case 1:
DESCODE(fp2,fp,filelen,key,keylen,1);
break;
default:
printf("数据输入错误，程序退出 。\n");
break;
}
fclose(fp);
fclose(fp2);
return 1;
}
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