信息安全课程设计DES算法.docx
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信息安全课程设计DES算法.docx
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信息安全课程设计DES算法
华中科技大学计算机科学与技术学院
《信息安全与保密》课程设计报告
院系:
远程与继续教育学院
专业:
计算机科学与技术
班级:
0602
学号:
4200106530258
姓名:
张鹏
指导教师:
崔永泉
2009年3月20日
题目、DES的编程实现
一、实验目的
(1)掌握DES中各加密函数对其性能影响;
(2)DES的特性分析,包括互补性和弱密钥;
(3)DES的实际应用,包括各种数据类型的加/脱密、DES的短块处理。
二、实验原理
本实验的原理包括DES算法的加密过程、脱密过程和16个内部密钥生成过程,已在前面进行详细地描述。
三、实验要求
①输入加密密钥和一串有意义的汉字,显示相应的加密结果;
输入密文和脱密密钥,显示所还原的一串有意义的汉字。
②设计用户界面,界面中要有加/脱密选择、输入明/密文栏、密钥栏和加/脱密结果显示栏。
四、实验环境
WindowsXP+Javascript环境下编绎成功
五、体会与评价
由于水平有限在javascript下只会实现8位的密钥加密,并且加密文本不支持汉字。
简单的做了个界面,希望以后水平提高可以完善程序吧。
六、源程序及相关运行结果
注:
程序加密解密时截图
textarea{width:
600px;height:
150px;}
body{font-size:
12px}
input{font-size:
12px}
--
varDES={
//initialpermutationIP
IP_Table:
[
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
],
//finalpermutationIP^-1
IPR_Table:
[
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
],
//permutedchoicetable(key)
PC1_Table:
[
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
],
//permutedchoicekey(table)
PC2_Table:
[
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
],
//numberleftrotationsofpc1
LOOP_Table:
[1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1],
//expansionoperationmatrix
E_Table:
[
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-bitpermutationfunctionPusedontheoutputoftheS-boxes
P_Table:
[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],
//The(in)famousS-boxes
S_Box:
[
//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]]
],
Oct2Bin:
["0000","0001","0010","0011","0100","0101","0110","0111",
"1000","1001","1010","1011","1100","1101","1110","1111"],
//str为八位的字符
subKeys:
newArray(16),
key:
"",
text:
""
};
DES.init=function(key,text){
if(key!
=this.key){
this.key=key;
this.GenSubKey();
}
this.text=text+"".substring(0,parseInt("07654321".charAt(text.length%8),10));
};
DES.GenSubKey=function(){
vararr=this.Permute(this.Byte2Bit(this.key),this.PC1_Table);
varAL=arr.slice(0,28);
varAR=arr.slice(28,56);
for(vari=0;i<16;i++){
for(varj=0,k=this.LOOP_Table[i];j AL.push(AL.shift()); AR.push(AR.shift()); } this.subKeys[i]=this.Permute(AL.concat(AR),this.PC2_Table); } }; //数组ar存储二进制数据,该函数将从头开始的每八位转换成对应的字符 DES.Bit2Byte=function(ar,fCh){ varstr=""; if(fCh=="byte"){ vartmpAr=ar.join("").match(/.{8}/g); for(vari=0,j=tmpAr.length;i str+=String.fromCharCode(parseInt(tmpAr[i],2)); } elseif(fCh=="hex"){ vartmpAr=ar.join("").match(/.{4}/g); for(vari=0,j=tmpAr.length;i str+="0123456789abcdef".charAt(parseInt(tmpAr[i],2)); } elsereturn"Error: Secondparamiswrong."; returnstr; }; //将字符串转换成二进制数组 DES.Byte2Bit=function(str){ for(vari=0,j=8*str.length,ar=[],ch="";i vark=7-i%8; if(k==7)ch=str.charCodeAt(parseInt(i/8,10)); ar.push((ch>>k)&1); } returnar; }; //将16进制字符串转变成二进制数组 DES.Hex2Bin=function(str){ for(vari=0,j=str.length,s="";i s+=this.Oct2Bin[parseInt(str.charAt(i),16)]; returns.split(""); }; DES.Xor=function(A,B){ for(vari=0,j=B.length,rtn=newArray(j);i rtn[i]=A[i]^B[i]; returnrtn; } DES.Permute=function(ar,tb){ for(vari=0,j=tb.length,rtn=newArray(j);i rtn[i]=ar[tb[i]-1]; returnrtn; }; DES.F_func=function(Ri,Ki) { returnthis.Permute(this.S_func(this.Xor(this.Permute(Ri,this.E_Table),Ki)),this.P_Table); }; //ar为输入48位串数组 DES.S_func=function(ar){ for(vari=0,arRtn=[];i<8;i++){ varx=i*6; varj=parseInt(""+ar[x]+ar[x+5],2); vark=parseInt(ar.slice(x+1,x+5).join(""),2); arRtn=arRtn.concat(this.Oct2Bin[this.S_Box[i][j][k]].split("")); } returnarRtn; } //mode参数为处理模式."Encrypt": 加密"Decrypt": 解密,默认为加密 DES.Encrypt=function(mode){ mode=mode? mode: "Encrypt"; if(mode=="Decrypt") varplainTextAr=this.Hex2Bin(this.text).join("").match(/.{64}/g); else varplainTextAr=this.Byte2Bit(this.text).join("").match(/.{64}/g); for(vari=0,j=plainTextAr.length;i vararr=this.Permute(plainTextAr[i].split(""),this.IP_Table) varAL=arr.slice(0,32); varAR=arr.slice(32,64); if(mode=="Decrypt"){ for(vark=15;k>-1;k--){ vartmp=AR.slice(0,32); AR=this.Xor(this.F_func(AR,this.subKeys[k]),AL); AL=tmp; } } else{ for(vark=0;k<16;k++){ vartmp=AR.slice(0,32); AR=this.Xor(this.F_func(AR,this.subKeys[k]),AL); AL=tmp; } } plainTextAr[i]=this.Bit2Byte(this.Permute(AR.concat(AL),this.IPR_Table),(mode=="Decrypt"? "byte": "hex")); } returnplainTextAr.join("").trim(); } String.prototype.trim=function(){returnthis.replace(/\s+$/g,"");} //--> -- var$=document.getElementById; functionjiami(){ DES.init($("txtKey").value,$("taText").value); $("taCipher").value=DES.Encrypt(); } functionjiemi(){ DES.init($("txtKey").value,$("taCipher").value); $("taText").value=DES.Encrypt("Decrypt"); } //--> 请输入加(解)密密钥: 未加密文本: (暂不支持中文) 加密后文本:
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