dirtyK 2021-06-10 14:53 采纳率: 100%
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请帮忙解释下一个md5的js文件逻辑,谢谢。

想知道它的逻辑是如何加密的,如何加盐,有没有向服务器请求数据还是纯本地的,谢谢。

var MD5 = function (sMessage) {  
    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(sMessage)  
    {  
      var lWordCount;  
      var lMessageLength = sMessage.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] | (sMessage.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;  
    }  
    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;  
    x = ConvertToWordArray(sMessage);  
    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();
}
  • 写回答

4条回答 默认 最新

  • 风雪一更 2021-06-10 15:33
    关注

    分别回答一下:

    1、base64.js文件是纯本地运算加密的,没有向服务端发送数据。你可以通过script标签引入到空的html文件里,然后在浏览器的NetWork里看一下是否有发起请求。

    2、加密就是是通过对传入字符串长度的计算以及对字符进行拼接,并不断循环计算拼接操作该字符串,最后生成一个新的字符串。

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
    评论
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