JavaWeb加密解密——md5

主要内容：前台js加密 ＋ 后台java解密

一、前台js加密： 将要发送给后台的信息在js里进行md5加密，得到密钥，然后将信息和密钥一起发送给后台。

1.引入md5的js框架，即md5.js文件，如下：

/**

* MD5 for JavaScript. (32bit)

* @ interface: MD5("Input String")

* @ return: key for Input String

**/



var MD5 = function (string) {

function RotateLeft(lValue, iShiftBits) {

return (lValue<<iShiftBits) | (lValue>>>(32-iShiftBits));

}

function AddUnsigned(lX,lY) {

var lX4,lY4,lX8,lY8,lResult;

lX8 = (lX & 0x80000000);

lY8 = (lY & 0x80000000);

lX4 = (lX & 0x40000000);

lY4 = (lY & 0x40000000);

lResult = (lX & 0x3FFFFFFF)+(lY & 0x3FFFFFFF);

if (lX4 & lY4) {

return (lResult ^ 0x80000000 ^ lX8 ^ lY8);

}

if (lX4 | lY4) {

if (lResult & 0x40000000) {

return (lResult ^ 0xC0000000 ^ lX8 ^ lY8);

} else {

return (lResult ^ 0x40000000 ^ lX8 ^ lY8);

}

} else {

return (lResult ^ lX8 ^ lY8);

}

}

function F(x,y,z) { return (x & y) | ((~x) & z); }

function G(x,y,z) { return (x & z) | (y & (~z)); }

function H(x,y,z) { return (x ^ y ^ z); }

function I(x,y,z) { return (y ^ (x | (~z))); }

function FF(a,b,c,d,x,s,ac) {

a = AddUnsigned(a, AddUnsigned(AddUnsigned(F(b, c, d), x), ac));

return AddUnsigned(RotateLeft(a, s), b);

};

function GG(a,b,c,d,x,s,ac) {

a = AddUnsigned(a, AddUnsigned(AddUnsigned(G(b, c, d), x), ac));

return AddUnsigned(RotateLeft(a, s), b);

};

function HH(a,b,c,d,x,s,ac) {

a = AddUnsigned(a, AddUnsigned(AddUnsigned(H(b, c, d), x), ac));

return AddUnsigned(RotateLeft(a, s), b);

};

function II(a,b,c,d,x,s,ac) {

a = AddUnsigned(a, AddUnsigned(AddUnsigned(I(b, c, d), x), ac));

return AddUnsigned(RotateLeft(a, s), b);

};

function ConvertToWordArray(string) {

var lWordCount;

var lMessageLength = string.length;

var lNumberOfWords_temp1=lMessageLength + 8;

var lNumberOfWords_temp2=(lNumberOfWords_temp1-(lNumberOfWords_temp1 % 64))/64;

var lNumberOfWords = (lNumberOfWords_temp2+1)*16;

var lWordArray=Array(lNumberOfWords-1);

var lBytePosition = 0;

var lByteCount = 0;

while ( lByteCount < lMessageLength ) {

lWordCount = (lByteCount-(lByteCount % 4))/4;

lBytePosition = (lByteCount % 4)*8;

lWordArray[lWordCount] = (lWordArray[lWordCount] | (string.charCodeAt(lByteCount)<<lBytePosition));

lByteCount++;

}

lWordCount = (lByteCount-(lByteCount % 4))/4;

lBytePosition = (lByteCount % 4)*8;

lWordArray[lWordCount] = lWordArray[lWordCount] | (0x80<<lBytePosition);

lWordArray[lNumberOfWords-2] = lMessageLength<<3;

lWordArray[lNumberOfWords-1] = lMessageLength>>>29;

return lWordArray;

};

function WordToHex(lValue) {

var WordToHexValue="",WordToHexValue_temp="",lByte,lCount;

for (lCount = 0;lCount<=3;lCount++) {

lByte = (lValue>>>(lCount*8)) & 255;

WordToHexValue_temp = "0" + lByte.toString(16);

WordToHexValue = WordToHexValue + WordToHexValue_temp.substr(WordToHexValue_temp.length-2,2);

}

return WordToHexValue;

};

function Utf8Encode(string) {

string = string.replace(/\r\n/g,"\n");

var utftext = "";

for (var n = 0; n < string.length; n++) {

var c = string.charCodeAt(n);

if (c < 128) {

utftext += String.fromCharCode(c);

}

else if((c > 127) && (c < 2048)) {

utftext += String.fromCharCode((c >> 6) | 192);

utftext += String.fromCharCode((c & 63) | 128);

}

else {

utftext += String.fromCharCode((c >> 12) | 224);

utftext += String.fromCharCode(((c >> 6) & 63) | 128);

utftext += String.fromCharCode((c & 63) | 128);

}

}

return utftext;

};

var x=Array();

var k,AA,BB,CC,DD,a,b,c,d;

var S11=7, S12=12, S13=17, S14=22;

var S21=5, S22=9 , S23=14, S24=20;

var S31=4, S32=11, S33=16, S34=23;

var S41=6, S42=10, S43=15, S44=21;

string = Utf8Encode(string);

x = ConvertToWordArray(string);

a = 0x67452301; b = 0xEFCDAB89; c = 0x98BADCFE; d = 0x10325476;

for (k=0;k<x.length;k+=16) {

AA=a; BB=b; CC=c; DD=d;

a=FF(a,b,c,d,x[k+0], S11,0xD76AA478);

d=FF(d,a,b,c,x[k+1], S12,0xE8C7B756);

c=FF(c,d,a,b,x[k+2], S13,0x242070DB);

b=FF(b,c,d,a,x[k+3], S14,0xC1BDCEEE);

a=FF(a,b,c,d,x[k+4], S11,0xF57C0FAF);

d=FF(d,a,b,c,x[k+5], S12,0x4787C62A);

c=FF(c,d,a,b,x[k+6], S13,0xA8304613);

b=FF(b,c,d,a,x[k+7], S14,0xFD469501);

a=FF(a,b,c,d,x[k+8], S11,0x698098D8);

d=FF(d,a,b,c,x[k+9], S12,0x8B44F7AF);

c=FF(c,d,a,b,x[k+10],S13,0xFFFF5BB1);

b=FF(b,c,d,a,x[k+11],S14,0x895CD7BE);

a=FF(a,b,c,d,x[k+12],S11,0x6B901122);

d=FF(d,a,b,c,x[k+13],S12,0xFD987193);

c=FF(c,d,a,b,x[k+14],S13,0xA679438E);

b=FF(b,c,d,a,x[k+15],S14,0x49B40821);

a=GG(a,b,c,d,x[k+1], S21,0xF61E2562);

d=GG(d,a,b,c,x[k+6], S22,0xC040B340);

c=GG(c,d,a,b,x[k+11],S23,0x265E5A51);

b=GG(b,c,d,a,x[k+0], S24,0xE9B6C7AA);

a=GG(a,b,c,d,x[k+5], S21,0xD62F105D);

d=GG(d,a,b,c,x[k+10],S22,0x2441453);

c=GG(c,d,a,b,x[k+15],S23,0xD8A1E681);

b=GG(b,c,d,a,x[k+4], S24,0xE7D3FBC8);

a=GG(a,b,c,d,x[k+9], S21,0x21E1CDE6);

d=GG(d,a,b,c,x[k+14],S22,0xC33707D6);

c=GG(c,d,a,b,x[k+3], S23,0xF4D50D87);

b=GG(b,c,d,a,x[k+8], S24,0x455A14ED);

a=GG(a,b,c,d,x[k+13],S21,0xA9E3E905);

d=GG(d,a,b,c,x[k+2], S22,0xFCEFA3F8);

c=GG(c,d,a,b,x[k+7], S23,0x676F02D9);

b=GG(b,c,d,a,x[k+12],S24,0x8D2A4C8A);

a=HH(a,b,c,d,x[k+5], S31,0xFFFA3942);

d=HH(d,a,b,c,x[k+8], S32,0x8771F681);

c=HH(c,d,a,b,x[k+11],S33,0x6D9D6122);

b=HH(b,c,d,a,x[k+14],S34,0xFDE5380C);

a=HH(a,b,c,d,x[k+1], S31,0xA4BEEA44);

d=HH(d,a,b,c,x[k+4], S32,0x4BDECFA9);

c=HH(c,d,a,b,x[k+7], S33,0xF6BB4B60);

b=HH(b,c,d,a,x[k+10],S34,0xBEBFBC70);

a=HH(a,b,c,d,x[k+13],S31,0x289B7EC6);

d=HH(d,a,b,c,x[k+0], S32,0xEAA127FA);

c=HH(c,d,a,b,x[k+3], S33,0xD4EF3085);

b=HH(b,c,d,a,x[k+6], S34,0x4881D05);

a=HH(a,b,c,d,x[k+9], S31,0xD9D4D039);

d=HH(d,a,b,c,x[k+12],S32,0xE6DB99E5);

c=HH(c,d,a,b,x[k+15],S33,0x1FA27CF8);

b=HH(b,c,d,a,x[k+2], S34,0xC4AC5665);

a=II(a,b,c,d,x[k+0], S41,0xF4292244);

d=II(d,a,b,c,x[k+7], S42,0x432AFF97);

c=II(c,d,a,b,x[k+14],S43,0xAB9423A7);

b=II(b,c,d,a,x[k+5], S44,0xFC93A039);

a=II(a,b,c,d,x[k+12],S41,0x655B59C3);

d=II(d,a,b,c,x[k+3], S42,0x8F0CCC92);

c=II(c,d,a,b,x[k+10],S43,0xFFEFF47D);

b=II(b,c,d,a,x[k+1], S44,0x85845DD1);

a=II(a,b,c,d,x[k+8], S41,0x6FA87E4F);

d=II(d,a,b,c,x[k+15],S42,0xFE2CE6E0);

c=II(c,d,a,b,x[k+6], S43,0xA3014314);

b=II(b,c,d,a,x[k+13],S44,0x4E0811A1);

a=II(a,b,c,d,x[k+4], S41,0xF7537E82);

d=II(d,a,b,c,x[k+11],S42,0xBD3AF235);

c=II(c,d,a,b,x[k+2], S43,0x2AD7D2BB);

b=II(b,c,d,a,x[k+9], S44,0xEB86D391);

a=AddUnsigned(a,AA);

b=AddUnsigned(b,BB);

c=AddUnsigned(c,CC);

d=AddUnsigned(d,DD);

}

var temp = WordToHex(a)+WordToHex(b)+WordToHex(c)+WordToHex(d);

return temp.toLowerCase();

}

2.调用md5.js提供的接口，得到密钥key，如下：

<script>

var key = MD5("Input String");

</script>

二、后台java解密：后台得到前台传来的信息和密钥，之后用java将信息md5加密从而得到新密钥，然后和前台传来的密钥对比，若两个密钥相同则正确，若不一致，则内容被黑客篡改。

1.接收前台传来的信息和密钥：

String Text = request.getParameter(" Input String ");

String oldKey = request.getParameter("key");

2.用java给得到的信息加密，得到新的key

3.对比两个密钥key是否相同：

if( oldKey==newKey ){

System.out.println("信息正确，没有被黑客篡改");

return true;

} else {

System.out.println("信息错误，已经被黑客篡改");

return false;

}

注意：md5加密算法分为16bit和32bit，此处的md5.js代码是32bit的加密方式。不管用那种，都要保证前后台加密方法的一致性，即前台js里用32bit的加密，后台java里就用32bit的解密，不能搞错。