DES算法实验报告.docx
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DES算法实验报告
DES算法实验报告
实
验
报
告
姓名:
xxxx学号:
0XXXXX班级:
XXXXXXX日期:
2013/11/*
题目:
DES算法实验
一、实验环境
1.硬件配置:
处理器:
Inter(R)Core(TM)i5-2430MCPU@2.40GHz(4CPUs),~2.4GHz
内存:
2048MBRAM
2.使用软件:
(1)操作系统:
win7旗舰版
(2)软件工具:
MicrosoftVisualc++6.0
二、实验涉及的相关概念或基本原理
DES是一个分组密码算法,使用64位密钥(除去8位奇偶校验,实际密钥长度为56位)对64比特的数据分组(二进制数据)加密,产生64位密文数据。
DES是一个对称密码体制,加密和解密使用同意密钥,解密和加密使用同一算法(这样,在硬件与软件设计时有利于加密单元的重用)。
DES的所有的保密性均依赖于密钥。
DES的加密过程可分为加密处理,加密变换和子密钥生成几个部分组成。
1.加密处理过程
(1)初始置换IP。
加密处理首先要对64位的明文按表1所示的初始换位表IP进行变换。
表中的数值表示输入位被置换后的新位置。
在产生子密钥的过程中左移次数如表7所示。
4.解密处理过程
从密文到明文的解密过程可采用与加密完全相同的算法。
不过解密要用加密的逆变换,就是把上面的最后换位表和初始换位表完全倒过来变换。
三、实验内容
流程图:
主要代码:
①初始置换
unsignedcharInitial[]=
{
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
};
②逆初始置换
unsignedcharFinal[]=
{
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
};
③扩展变换E
unsignedcharExpansion[]=
{
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
};
④P_盒置换
unsignedcharP_Box[]=
{
16,7,20,21,29,12,28,17,1,15,23,26,
5,18,31,30,2,8,24,14,32,27,3,9,
19,13,30,6,22,11,4,25
};
⑤S盒置换
unsignedcharS_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}}
};
⑥置换选择1
unsignedcharKey_Exchange[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
};
⑦置换选择2
unsignedcharCompression[]=
{
14,17,11,24,1,5,3,28,15,6,21,10,
23,19,12,4,26,9,16,7,27,20,13,2,
41,52,31,37,47,55,30,40,51,45,33,48,
44,49,39,56,34,53,46,42,50,36,29,32
};
⑧循环左移位数
unsignedcharKey_Move[]=
{
1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1
};
⑨产生子密钥
intKey_Process(boolkey[64],boolSub_Key[16][48])
{
intround;
booltemp[56];
Key_Transform1(key,temp);
for(round=0;round<16;round++)
{
Key_Rotate(temp,Key_Move[round]);
Key_Transform2(temp,Sub_Key[round]);
}
return0;
}
异或
intXOR(boolKR[48],boolKL[48],intcount)
{
inti;
for(i=0;i{
KR[i]^=KL[i];
}
return0;
}
加密算法
intDES_Encrypt(boolMessage[8],boolSub_Key[16][48],
boolFinal_Result[8])
{
boolExpanded_Right[48];
boolResult[64];
intround;
Char8ToBit64(Message,Result);
Initial_Exchange(Result);
for(round=0;round<16;round++)
{
memcpy(Expanded_Right,Result+32,32);
M_Expand(Expanded_Right);
XOR(Expanded_Right,Sub_Key[round],48);
S_function(Expanded_Right);
P_function(Expanded_Right);
XOR(Result,Expanded_Right,32);
if(round!
=15)
Swap(Result,Result+32);
}
Final_Exchange(Result);
Bit64ToChar8(Result,Final_Result);
return0;
}
解密算法
intDES_Decrypt(boolFinal_Result[8],boolSub_Key[16][48],
boolMessage[8])
{
boolExpanded_Right[48];
boolResult[64];
intround;
Char8ToBit64(Final_Result,Result);
Initial_Exchange(Result);
for(round=15;round>=0;round--)
{
memcpy(Expanded_Right,Result+32,32);
M_Expand(Expanded_Right);
XOR(Expanded_Right,Sub_Key[round],48);
S_function(Expanded_Right);
P_function(Expanded_Right);
XOR(Result,Expanded_Right,32);
if(round!
=0)
Swap(Result,Result+32);
}
Final_Exchange(Result);
Bit64ToChar8(Result,Message);
return0;
}
加密文件
intDES_EncryptFile(char*Final_Result)
{
FILE*input,*output;
intcount;
unsignedname[30];
unsignedcharkey[64];
boolInputBlock[8],OutputBlock[8],keyBlock[8];
boolbKey[64];
boolSub_Key[16][48];
printf("输入文件名\n");
scanf("%s",name);
printf("输入密钥\n");
scanf("%s",key);
getchar();
if((input=fopen(name,"rb"))==NULL)
return0;
if((output=fopen(Final_Result,"wb"))==NULL)
return0;
memcpy(keyBlock,key,8);
Char8ToBit64(keyBlock,bKey);
Key_Process(bKey,Sub_Key);
while(!
feof(input))
{
if((count=fread(InputBlock,sizeof(char),8,input))==8)
{
DES_Encrypt(InputBlock,Sub_Key,OutputBlock);
fwrite(OutputBlock,sizeof(char),8,output);
}
}
if(count)
{
memset(InputBlock+count,'\0',7-count);
InputBlock[7]=8-count;
DES_Encrypt(InputBlock,Sub_Key,OutputBlock);
fwrite(OutputBlock,sizeof(char),8,output);
}
fclose(input);
fclose(output);
return1;
}
解密文件
intDES_DecryptFile(char*Message)
{
FILE*input,*output;
intcount,times=0;
longfileLen;
unsignedname[30];
unsignedcharkey[64];
boolinputBlock[8],outputBlock[8],keyBlock[8];
boolbKey[64];
boolSub_Key[16][48];
printf("输入文件名\n");
scanf("%s",name);
printf("输入密钥\n");
scanf("%s",key);
getchar();
if((output=fopen(name,"rb"))==NULL)
return0;
if((input=fopen(Message,"wb"))==NULL)
return0;
memcpy(keyBlock,key,8);
Char8ToBit64(keyBlock,bKey);
Key_Process(bKey,Sub_Key);
fseek(output,0,SEEK_END);
fileLen=ftell(output);
rewind(output);
while
(1)
{
fread(outputBlock,sizeof(char),8,output);
DES_Decrypt(outputBlock,Sub_Key,inputBlock);
times+=8;
if(timesfwrite(inputBlock,sizeof(char),8,input);
else
break;
}
if(inputBlock[7]<8)
{
for(count=8-inputBlock[7];count<7;count++)
{
if(inputBlock[count]!
='\0')
{
break;
}
}
}
if(count==7)
fwrite(inputBlock,sizeof(char),8-inputBlock[7],input);
else
{
fwrite(inputBlock,sizeof(char),8,input);
}
fclose(input);
fclose(output);
return1;
}
四、实验总结分析
1、心得体会
对DES加密算法有了进一步的认识与了解,对DES算法的结构和优缺点也有了了解,相信在以后的学习与实践中,能够更好地运用这些算法。