encrypt.cpp

使用VC编程实现DES的加密与解密算法

#include "stdafx.h"
#include "DES.h"
#include "Encrypt.h"

Encrypt::Encrypt()
{
}
const char Encrypt::Table_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};
const  char Encrypt::Table_IPR[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};
const  char Encrypt::Table_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};
const  char Encrypt::Table_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};
const  char Encrypt::Table_PC1[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};
const  char Encrypt::Table_PC2[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};
const  char Encrypt::Table_LS[16]={
	1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1};
const  char Encrypt::Sbox[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}; 
Encrypt::~Encrypt()
{
}
void Encrypt::Des_Encrypt(char out[8],char in[8],bool subkey[16][48])
{
	static bool tem64[64],tem32[32],*Li=&tem64[0],*Ri=&tem64[32];
	ByteToBit(tem64,in,64);
	Table_Transform(tem64,tem64,Table_IP,64);
	for(int i=0;i<16;i++)
	{
		memcpy(tem32,Ri,32);
		Des_f(Ri,subkey[i]);
		Xor(Ri,Li,32);
		memcpy(Li,tem32,32);
	}
	Table_Transform(tem64,tem64,Table_IPR,64);
	BitToByte(out,tem64,64);
}
void Encrypt::Des_Decrypt(char out[8],char in[8],bool subkey[16][48])
{
	static bool tem64[64],tem32[32],*Li=&tem64[0],*Ri=&tem64[32];
	ByteToBit(tem64,in,64);
	Table_Transform(tem64,tem64,Table_IP,64);
	for(int i=15;i>=0;i--)
	{
		memcpy(tem32,Li,32);
		Des_f(Li,subkey[i]);
		Xor(Li,Ri,32);
		memcpy(Ri,tem32,32);
	}
	Table_Transform(tem64,tem64,Table_IPR,64);
	BitToByte(out,tem64,64);
}
void Encrypt::Des_CreateSubkey(const char key[8],bool subkey[16][48])
{
	static bool K[64],*KL=&K[0],*KR=&K[32];
	ByteToBit(K,key,64);
	Table_Transform(K,K,Table_PC1,56);
	for(int i=0;i<16;i++)
	{
		Shift_left(KL,28,Table_LS[i]);
		Shift_left(KR,28,Table_LS[i]);
		Table_Transform(subkey[i],K,Table_PC2,48);
	}
}
void Encrypt::Des_f(bool in[32], bool subkey[48])
{
	static bool F[48];
	Table_Transform(F,in,Table_E,48);
	Xor(F,subkey,48);
	Des_s(in,F);
	Table_Transform(in,in,Table_P,32);
}
void Encrypt::Des_s(bool out[32],const bool in[48])
{
	for(char i=0,j,k;i<8;i++,in+=6,out+=4)
	{
		j=(in[0]<<1)+in[5];
		k=(in[1]<<3)+(in[2]<<2)+(in[3]<<1)+in[4];
		ByteToBit(out,&Sbox[i][j][k],4);
	}
}
void Encrypt::Table_Transform(bool *out,bool *in,const char *Table,int len)
{
	static bool tem[256];
	for(int i=0;i<len;i++)
	{
		tem[i]=in[Table[i]-1];
	}
	memcpy(out,tem,len);
}
void Encrypt::Xor(bool *a,bool *b,int len)
{
	for(int i=0;i<len;i++)
		a[i]=a[i]^b[i];
}
void Encrypt::Shift_left(bool *in,int len,int loop)
{
	static bool tem[256];
	memcpy(tem,in,loop);
	memcpy(in,in+loop,len-loop);
	memcpy(in+len-loop,tem,loop);
}
void Encrypt::ByteToBit(bool *out,const char *in,int len)
{
	for(int i=0;i<len;i++)
		out[i]=in[i/8]>>(i%8)&1;
}
void Encrypt::BitToByte(char *out,const bool *in,int len)
{
	memset(out,0,(len+7)/8);
	for(int i=0;i<len;i++)
		out[i/8]|=in[i]<<(i%8);
}