des.cpp

实现分组密码加密解密功能

#include<iostream.h>
int SubKey[16][48];
int r1[48];
const static int 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
};
const static int 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
};
static const int 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
};
const static int 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
};
const static int 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,
 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 static int 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
};
const static int LOOP_Table[16] = { 
 1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1
};

const static int 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
};
void cpy(int *output, int *tmp, int length)                        
   {
	for(int j0=0;j0<length;j0++)
	{
		output[j0]=tmp[j0];
	}
   }
void Permute(int *output,int *input,int length,const int* table){           
 int *tmp=new int[length];
 for(int i1=0; i1<length; ++i1)
        tmp[i1] = input[ table[i1]-1 ];
    cpy(output, tmp, length);
 delete tmp;
}
void Xor(int* output,int *input_a,const int *input_b,int length){
 for(int i3=0; i3<length; i3++)
        output[i3]=input_a[i3] ^ input_b[i3];
}

void F(int right[32],int subkey[48]){
 int r[48];
 Permute(r,right,48,E_Table);
 
    Xor(r1,r,subkey, 48);
	
 for(int i2=0,j,k,h=0; i2<8; i2++,h+=6) 
 { 
        j = (r1[h]*2) + r1[h+5];
        k = (r1[h+1]*8) + (r1[h+2]*4) + (r1[h+3]*2) + r1[h+4];
		int x=S_Box[i2][j][k];
		for(int p=3;p>-1;p--)
		{
		   right[i2*4+p]=x%2;
		   x=x/2;
		}
		    
    }
 Permute(right,right,32,P_Table);
}
void producekey(int *permute_key)
{
	for(int i=0;i<16;i++)
	{
        int t=LOOP_Table[i];
		int g[56];
		for(int j=0;j<56;j++)
		{
			g[j]=permute_key[j];
		}
		for(j=0;j<28;j++)
		{
			permute_key[j]=g[(t+j)%28];
		}
		for(j=28;j<56;j++)
		{
			permute_key[j]=g[(t+j)%28+28];
		}
		for(int m=0;m<48;m++)
		{
			SubKey[i][m]=permute_key[PC2_Table[m]-1];
		}
	}
}

void ByteToBit(int *output, char *input,int bits)
{
    for(int i=0;i<bits;i++)
	{
		output[i]=(input[i/8]>>(7-(i%8)))&1;
	}
}

void BitToByte(char * output,int * input,int bits)
{
	for(int i=0;i<8;i++)
	{
		output[i]=input[i*8]*bits*2+input[1+i*8]*bits+input[2+i*8]*(bits/2)+input[3+i*8]*(bits/4)+input[4+i*8]*(bits/8)+
			input[5+i*8]*(bits/16)+input[6+i*8]*(bits/32)+input[7+i*8]*(bits/64);
	}
}

int Encrypt( int M[64],int C[64]){
	int left[32],right[32],tmp[32];
 
    Permute(M, M, 64,IP_Table);	
	for(int  i=0;i<32;i++)
	{
		left[i]=M[i];
	}
	for(i=0;i<32;i++)
	{
		right[i]=M[i+32];
	}

	for( int i0=0; i0<16; ++i0) {
        cpy(tmp, right, 32);
        F(right, SubKey[i0]);
        Xor(right, right, left, 32);
        cpy(left, tmp, 32);
   }


 cpy(tmp, right, 32);
 cpy(right, left, 32);                    // 32位互换
 cpy(left, tmp, 32);
  for(i=0;i<32;i++)
	 {
		 M[i]=left[i];
		 M[i+32]=right[i];
	 }

 Permute(C, M, 64,IPR_Table);               //逆初始置换
    
	return 0;

}


int Decrypt( int C[64],int M[64]){
	int left[32],right[32],tmp[32];
 
    Permute(C, C, 64,IP_Table);
	
	for(int  i=0;i<32;i++)
	{
		left[i]=C[i];
	}
	for(i=0;i<32;i++)
	{
		right[i]=C[i+32];
	}

	
	for( int i0=15; i0>-1; i0--) {
        cpy(tmp, right, 32);
        F(right, SubKey[i0]);
        Xor(right, right, left, 32);
        cpy(left, tmp, 32);
   }


 cpy(tmp, right, 32);
 cpy(right, left, 32);                    // 32位互换
 cpy(left, tmp, 32);
  for(i=0;i<32;i++)
	 {
		 C[i]=left[i];
		 C[i+32]=right[i];
	 }

 Permute(M, C, 64,IPR_Table);               //逆初始置换
    
	return 0;

}

int main(){
	char miyao[9]="american";
	int key0[64],key[56];
	 ByteToBit(key0,miyao,64);
    Permute(key,key0,56,PC1_Table);
	 producekey(key);
	 char miwen[8];
 char mingwen[9]="abcdefgh"; 
 int m[64],c[64];
 ByteToBit(m, mingwen, 64);
 cout<<"明文二进制输出"<<endl;
 for(int i=0;i<64;i++)
	{
		cout<<m[i];
		if(i%8==7)cout<<endl;
	}
 Encrypt(m,c);

 cout<<"输出密文二进制"<<endl;

 for( i=0;i<64;i++)
	{
		cout<<c[i];
		if(i%8==7)cout<<endl;
	}

BitToByte(miwen,c,64);

cout<<"密文输出"<<endl;
cout<<miwen<<endl;	
 Decrypt(c,m); 
 BitToByte(mingwen,m,64);
 cout<<"明文输出"<<endl;
 cout<<mingwen<<endl;
 cout<<endl;
 return 0;
}