DES加密解密 使用bitset编写...

其他 2018-05-08 05:20:52 阅读次数: 4 
#include<iostream>
#include<bitset>
#include<string> 

using namespace std;

int IPTable[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
};

int CPTable[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
};

int SiftTable[16] = {
	1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1
};

int EPTable[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
};

int SBoxTable[8][4][16] = {
	{
	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
	},
	
	{
	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
	},
	
	{
	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
	},
	
	{
	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,
	},
	
	{
	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
	},
	
	{
	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
	},
	
	{
	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
	},
	
	{
	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 PBoxTable[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
};

int FinalTable[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	
}; 

void print64BitStream(bitset<64> temp)
{
	for(int i = 0;i<temp.size();i++)
		cout<<temp[i];

	cout<<endl;
}

void print56BitStream(bitset<56> temp)
{
	for(int i = 0;i<temp.size();i++)
		cout<<temp[i];

	cout<<endl;
}

void print32BitStream(bitset<32> temp)
{
	for(int i = 0;i<temp.size();i++)
		cout<<temp[i];

	cout<<endl;
}

void print48BitStream(bitset<48> temp)
{
	for(int i = 0;i<temp.size();i++)
		cout<<temp[i];

	cout<<endl;
}

bitset<64> reverse(bitset<64> temp)
{
	bitset<64> reverseVal(0);
	
	for(int i=0;i<64;i++)
		reverseVal[i] = temp[63-i];
		
	return reverseVal; 
} 
void InitialPermutation(bitset<64> &temp)
{
	//copy bitset<64>
	bitset<64> BitSetCopy(0);

	for(int j=0;j<64;j++)
	{
		BitSetCopy[j] = temp[j];
	}

	for(int i=0;i<64;i++)//IP 置换 !!!
	{
		temp[i] = BitSetCopy[IPTable[i]-1];
	}
}

bitset<48> CompressionPermutation(bitset<56> temp)
{
	bitset<48> CPKey(0);
	for(int i = 0;i<48;i++)
	{
		CPKey[i] = temp[CPTable[i]-1];
	}
	return CPKey;
}

bitset<48> ExpansionPermutation(bitset<32> temp)
{
	bitset<48> EPCipher(0);
	for(int i=0;i<48;i++)
		EPCipher[i] = temp[EPTable[i]-1];
		
	return EPCipher;
} 

bitset<32> SubstitutionBox(bitset<48> key,bitset<48> RPT)
{
	//XOR operation
	bitset<48> AfterXOR(0);
	AfterXOR = key^RPT;
	 
	//SBox
	bitset<2> temp2Bit(0);
	bitset<4> temp4Bit(0); 
	bitset<32> resultVal(0); 
	
	bitset<4> output[8];
	bitset<6> input[8];

	for(int i=0,j=0;i<48;i++)
	{
		input[j][i-j*6] = AfterXOR[i];
		
		if((i+1)%6==0)
		{
			j++;
		}
	}
	
	for(int i=0;i<8;i++)
	{
		for(int j=0;j<6;j++)
		{
			if(j==0)
				temp2Bit[1] = input[i][j];
				
				else if(j==5)
				temp2Bit[0] = input[i][j];
				
					else temp4Bit[4-j] = input[i][j];
		}	 	
		
		
		output[i] = SBoxTable[i][temp2Bit.to_ulong()][temp4Bit.to_ulong()];//!!!!!! 
		//if(i==0)cout<<"output: "<<output[i]<<endl;
		for(int l=0;l<4;l++)
		{
			resultVal[i*4+l] = output[i][3-l];
		}
	}  
	cout<<"SBox Output: ";
	print32BitStream(resultVal);
	return resultVal;
}//!!!!!!!!!!! 

bitset<32> PBoxPermutation(bitset<32> temp)
{
	bitset<32>  returnVal(0);
	
	for(int i=0;i<32;i++)
	{
		returnVal[i] = temp[PBoxTable[i]-1];
	} 
	
	return returnVal;
}

void equalTo(bitset<32>&a,bitset<32>b)
{
	for(int i=0;i<32;i++)
	{
		a[i] = b[i];
	}
}

bitset<56> cutKey(bitset<64> &temp)
{
	bitset<56> tempTo56(0);
	for(int i = 0,k = 0;i<64;i++)
	{
		//64 To 58 
		if((i+1)%8!=0)
		{
			tempTo56[k++] = temp[i];
		}
	} 
	return tempTo56; 
}

void siftKey(bitset<56> &temp,int round)
{
	bitset<28> LPT(0);
	bitset<28> RPT(0);

	int LPTtempVal[2];
	int RPTtempVal[2];

	int siftValue = SiftTable[round];//获得移位的值  循环左移。。 

	for(int i=0;i<56;i++)
	{
		if(i<28)
		{
			LPT[i] = temp[i];
		}
		else
		{
			RPT[i-28] = temp[i]; 
		}
	}

	for(int i=0;i<siftValue;i++)
	{
		LPTtempVal[i] = LPT[i];
		RPTtempVal[i] = RPT[i];
	} 
	//移位操作

	LPT = (LPT.to_ulong())>>siftValue;
	RPT = (RPT.to_ulong())>>siftValue;

	for(int k = siftValue,i=28-k,j=0;k>0;k--,j++)
	{
		LPT[i] = LPTtempVal[j];
		RPT[i] = RPTtempVal[j];
	}

	for(int i=0;i<56;i++)
	{
		if(i<28)
		{
			temp[i] = LPT[i];
		}
		else
		{
			temp[i] = RPT[i-28]; 
		}
	}
}

bitset<48> getKey(bitset<64> initKey,int round)//cut-->CP 
{
	bitset<48> CPfinalKey(0);
	bitset<56> CutKey = cutKey(initKey);
	siftKey(CutKey,round); //after sifting
	
	for(int i =0;i<48;i++)
	{
		CPfinalKey[i] = CutKey[CPTable[i]-1];
	}
	
	
	return CPfinalKey;
}

bitset<64> FinalPermutation(bitset<64> temp)
{
	bitset<64> returnVal(0);
	for(int i=0;i<64;i++)
	{
		returnVal[i] = temp[FinalTable[i]-1];
	}
	 
	return returnVal;
} 

bitset<64> De_FinalPermutation(bitset<64> temp)
{
	bitset<64>returnVal(0);
	for(int i=0;i<64;i++)
	{
		returnVal[FinalTable[i]-1] = temp[i];
	}
	return returnVal;
} 

bitset<64> DESDecode(bitset<64>EncodeVal,bitset<64>Key)
{
	InitialPermutation(EncodeVal);
	bitset<32> RPT;
	bitset<32> LPT;
	
	bitset<32> tempPT;
	bitset<64> finalResult;
	bitset<48> ExpRPT(0);
	
	for(int i=0;i<64;i++)
	{
		if(i<32)
			LPT[i] = EncodeVal[i];
		else
			RPT[i-32] = EncodeVal[i];
	//plain text initial finish.
	}
	
	
	bitset<48> theKey(0); 
	for(int i=15;i>=0;i--)
	{
		theKey = getKey(Key,i);

		//Key Finish
		cout<<i<<".Key:"<<theKey<<endl;
		cout<<i<<".RPT:";
		print32BitStream(RPT); 
		//Expnasion Permutation  48bit 
		ExpRPT = ExpansionPermutation(RPT); 
		tempPT = (PBoxPermutation(SubstitutionBox(theKey,ExpRPT)))^LPT;
		
		LPT = RPT;
		
		RPT = tempPT; 
	} 
	
	cout<<"Final LPT: ";
	print32BitStream(LPT);
	cout<<"Final RPT: ";
	print32BitStream(RPT); 
	for(int i=0;i<64;i++)
	{
		if(i<32)
			finalResult[i] = LPT[i];
		else
			finalResult[i] = RPT[i-32];
	}
	
	finalResult = FinalPermutation(finalResult);
	
 return finalResult; 
}

bitset<64> DESEncode(bitset<64>PlainText,bitset<64>Key)
{
	InitialPermutation(PlainText);
	bitset<32> RPT;
	bitset<32> LPT;
	
	bitset<32> tempPT;
	bitset<64> finalResult;
	bitset<48> ExpRPT(0);
	
	for(int i=0;i<64;i++)
	{
		if(i<32)
			LPT[i] = PlainText[i];
		else
			RPT[i-32] = PlainText[i];
	//plain text initial finish.
	}
	
	
	bitset<48> theKey(0); 
	for(int i=0;i<16;i++)
	{
		theKey = getKey(Key,i);

		//Key Finish
		cout<<i<<".Key:"<<theKey<<endl;
		cout<<i<<".RPT:";
		print32BitStream(RPT); 
		//Expnasion Permutation  48bit 
		ExpRPT = ExpansionPermutation(RPT); 
		tempPT = (PBoxPermutation(SubstitutionBox(theKey,ExpRPT)))^LPT;
		
		LPT = RPT;
		
		RPT = tempPT; 
	} 
	
	cout<<"Final LPT: ";
	print32BitStream(LPT);
	cout<<"Final RPT: ";
	print32BitStream(RPT); 
	for(int i=0;i<64;i++)
	{
		if(i<32)
			finalResult[i] = RPT[i];
		else
			finalResult[i] = LPT[i-32];
	}
	
	finalResult = FinalPermutation(finalResult);
	
 return finalResult; 
}



int main()
{
	bitset<64> data(0);
	bitset<64> key(0);
	
	print64BitStream(DESEncode(data,key)); 
	
	print64BitStream(DESDecode(DESEncode(data,key),key)); 
	
	/*
cout<<"PlainText:";
	print64BitStream(data);
	cout<<"Key:";
	print64BitStream(key); 
	
	cout<<DESEncode(data,key)<<endl;*/
}


主要注意点:bitset的高位是在左边的.而DES的高位是在右边的.在进行to_ulong的时候需要确定是否倒置了否则可能造成错误.

DES的解密很简单.和加密步骤基本一致,但是需要把key的获取从第16轮开始获取直到第1轮的key.


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