解析MD5算法
MD5实现128bit的Hash值的密码散列函数
1、MD5的作用：
在传输的时候，进行加密，防止恶意窃取数据。
2、MD5算法的原理：
填充输入信息，使其字节长度对512求余数为448.
信息的长度扩展为N*512+448 bit N为整数。然后将每个512bit的组分为16个32bit子分组，最后经过一系列的算法生成4个32bit共128bit的散列值
3、MD5算法的实现：
1 /* eslint-disable */ 2 var jQuery = require('jquery'); 3 (function($){ 4 var rotateLeft = function(lValue, iShiftBits) { 5 return (lValue << iShiftBits) | (lValue >>> (32 - iShiftBits)); 6 } 7 var addUnsigned = function(lX, lY) { 8 var lX4, lY4, lX8, lY8, lResult; 9 lX8 = (lX & 0x80000000); 10 lY8 = (lY & 0x80000000); 11 lX4 = (lX & 0x40000000); 12 lY4 = (lY & 0x40000000); 13 lResult = (lX & 0x3FFFFFFF) + (lY & 0x3FFFFFFF); 14 if (lX4 & lY4) return (lResult ^ 0x80000000 ^ lX8 ^ lY8); 15 if (lX4 | lY4) { 16 if (lResult & 0x40000000) return (lResult ^ 0xC0000000 ^ lX8 ^ lY8); 17 else return (lResult ^ 0x40000000 ^ lX8 ^ lY8); 18 } else { 19 return (lResult ^ lX8 ^ lY8); 20 } 21 } 22 var F = function(x, y, z) { 23 return (x & y) | ((~ x) & z); 24 } 25 var G = function(x, y, z) { 26 return (x & z) | (y & (~ z)); 27 } 28 var H = function(x, y, z) { 29 return (x ^ y ^ z); 30 } 31 var I = function(x, y, z) { 32 return (y ^ (x | (~ z))); 33 } 34 var FF = function(a, b, c, d, x, s, ac) { 35 a = addUnsigned(a, addUnsigned(addUnsigned(F(b, c, d), x), ac)); 36 return addUnsigned(rotateLeft(a, s), b); 37 }; 38 var GG = function(a, b, c, d, x, s, ac) { 39 a = addUnsigned(a, addUnsigned(addUnsigned(G(b, c, d), x), ac)); 40 return addUnsigned(rotateLeft(a, s), b); 41 }; 42 var HH = function(a, b, c, d, x, s, ac) { 43 a = addUnsigned(a, addUnsigned(addUnsigned(H(b, c, d), x), ac)); 44 return addUnsigned(rotateLeft(a, s), b); 45 }; 46 var II = function(a, b, c, d, x, s, ac) { 47 a = addUnsigned(a, addUnsigned(addUnsigned(I(b, c, d), x), ac)); 48 return addUnsigned(rotateLeft(a, s), b); 49 }; 50 var convertToWordArray = function(string) { 51 var lWordCount; 52 var lMessageLength = string.length; 53 var lNumberOfWordsTempOne = lMessageLength + 8; 54 var lNumberOfWordsTempTwo = (lNumberOfWordsTempOne - (lNumberOfWordsTempOne % 64)) / 64; 55 var lNumberOfWords = (lNumberOfWordsTempTwo + 1) * 16; 56 var lWordArray = Array(lNumberOfWords - 1); 57 var lBytePosition = 0; 58 var lByteCount = 0; 59 while (lByteCount < lMessageLength) { 60 lWordCount = (lByteCount - (lByteCount % 4)) / 4; 61 lBytePosition = (lByteCount % 4) * 8; 62 lWordArray[lWordCount] = (lWordArray[lWordCount] | (string.charCodeAt(lByteCount) << lBytePosition)); 63 lByteCount++; 64 } 65 lWordCount = (lByteCount - (lByteCount % 4)) / 4; 66 lBytePosition = (lByteCount % 4) * 8; 67 lWordArray[lWordCount] = lWordArray[lWordCount] | (0x80 << lBytePosition); 68 lWordArray[lNumberOfWords - 2] = lMessageLength << 3; 69 lWordArray[lNumberOfWords - 1] = lMessageLength >>> 29; 70 return lWordArray; 71 }; 72 var wordToHex = function(lValue) { 73 var WordToHexValue = "", WordToHexValueTemp = "", lByte, lCount; 74 for (lCount = 0; lCount <= 3; lCount++) { 75 lByte = (lValue >>> (lCount * 8)) & 255; 76 WordToHexValueTemp = "0" + lByte.toString(16); 77 WordToHexValue = WordToHexValue + WordToHexValueTemp.substr(WordToHexValueTemp.length - 2, 2); 78 } 79 return WordToHexValue; 80 }; 81 var uTF8Encode = function(string) { 82 string = string.replace(/\x0d\x0a/g, "\x0a"); 83 var output = ""; 84 for (var n = 0; n < string.length; n++) { 85 var c = string.charCodeAt(n); 86 if (c < 128) { 87 output += String.fromCharCode(c); 88 } else if ((c > 127) && (c < 2048)) { 89 output += String.fromCharCode((c >> 6) | 192); 90 output += String.fromCharCode((c & 63) | 128); 91 } else { 92 output += String.fromCharCode((c >> 12) | 224); 93 output += String.fromCharCode(((c >> 6) & 63) | 128); 94 output += String.fromCharCode((c & 63) | 128); 95 } 96 } 97 return output; 98 }; 99 $.extend({ 100 md5: function(string) { 101 var x = Array(); 102 var k, AA, BB, CC, DD, a, b, c, d; 103 var S11=7, S12=12, S13=17, S14=22; 104 var S21=5, S22=9 , S23=14, S24=20; 105 var S31=4, S32=11, S33=16, S34=23; 106 var S41=6, S42=10, S43=15, S44=21; 107 string = uTF8Encode(string); 108 x = convertToWordArray(string); 109 a = 0x67452301; b = 0xEFCDAB89; c = 0x98BADCFE; d = 0x10325476; 110 for (k = 0; k < x.length; k += 16) { 111 AA = a; BB = b; CC = c; DD = d; 112 a = FF(a, b, c, d, x[k+0], S11, 0xD76AA478); 113 d = FF(d, a, b, c, x[k+1], S12, 0xE8C7B756); 114 c = FF(c, d, a, b, x[k+2], S13, 0x242070DB); 115 b = FF(b, c, d, a, x[k+3], S14, 0xC1BDCEEE); 116 a = FF(a, b, c, d, x[k+4], S11, 0xF57C0FAF); 117 d = FF(d, a, b, c, x[k+5], S12, 0x4787C62A); 118 c = FF(c, d, a, b, x[k+6], S13, 0xA8304613); 119 b = FF(b, c, d, a, x[k+7], S14, 0xFD469501); 120 a = FF(a, b, c, d, x[k+8], S11, 0x698098D8); 121 d = FF(d, a, b, c, x[k+9], S12, 0x8B44F7AF); 122 c = FF(c, d, a, b, x[k+10], S13, 0xFFFF5BB1); 123 b = FF(b, c, d, a, x[k+11], S14, 0x895CD7BE); 124 a = FF(a, b, c, d, x[k+12], S11, 0x6B901122); 125 d = FF(d, a, b, c, x[k+13], S12, 0xFD987193); 126 c = FF(c, d, a, b, x[k+14], S13, 0xA679438E); 127 b = FF(b, c, d, a, x[k+15], S14, 0x49B40821); 128 a = GG(a, b, c, d, x[k+1], S21, 0xF61E2562); 129 d = GG(d, a, b, c, x[k+6], S22, 0xC040B340); 130 c = GG(c, d, a, b, x[k+11], S23, 0x265E5A51); 131 b = GG(b, c, d, a, x[k+0], S24, 0xE9B6C7AA); 132 a = GG(a, b, c, d, x[k+5], S21, 0xD62F105D); 133 d = GG(d, a, b, c, x[k+10], S22, 0x2441453); 134 c = GG(c, d, a, b, x[k+15], S23, 0xD8A1E681); 135 b = GG(b, c, d, a, x[k+4], S24, 0xE7D3FBC8); 136 a = GG(a, b, c, d, x[k+9], S21, 0x21E1CDE6); 137 d = GG(d, a, b, c, x[k+14], S22, 0xC33707D6); 138 c = GG(c, d, a, b, x[k+3], S23, 0xF4D50D87); 139 b = GG(b, c, d, a, x[k+8], S24, 0x455A14ED); 140 a = GG(a, b, c, d, x[k+13], S21, 0xA9E3E905); 141 d = GG(d, a, b, c, x[k+2], S22, 0xFCEFA3F8); 142 c = GG(c, d, a, b, x[k+7], S23, 0x676F02D9); 143 b = GG(b, c, d, a, x[k+12], S24, 0x8D2A4C8A); 144 a = HH(a, b, c, d, x[k+5], S31, 0xFFFA3942); 145 d = HH(d, a, b, c, x[k+8], S32, 0x8771F681); 146 c = HH(c, d, a, b, x[k+11], S33, 0x6D9D6122); 147 b = HH(b, c, d, a, x[k+14], S34, 0xFDE5380C); 148 a = HH(a, b, c, d, x[k+1], S31, 0xA4BEEA44); 149 d = HH(d, a, b, c, x[k+4], S32, 0x4BDECFA9); 150 c = HH(c, d, a, b, x[k+7], S33, 0xF6BB4B60); 151 b = HH(b, c, d, a, x[k+10], S34, 0xBEBFBC70); 152 a = HH(a, b, c, d, x[k+13], S31, 0x289B7EC6); 153 d = HH(d, a, b, c, x[k+0], S32, 0xEAA127FA); 154 c = HH(c, d, a, b, x[k+3], S33, 0xD4EF3085); 155 b = HH(b, c, d, a, x[k+6], S34, 0x4881D05); 156 a = HH(a, b, c, d, x[k+9], S31, 0xD9D4D039); 157 d = HH(d, a, b, c, x[k+12], S32, 0xE6DB99E5); 158 c = HH(c, d, a, b, x[k+15], S33, 0x1FA27CF8); 159 b = HH(b, c, d, a, x[k+2], S34, 0xC4AC5665); 160 a = II(a, b, c, d, x[k+0], S41, 0xF4292244); 161 d = II(d, a, b, c, x[k+7], S42, 0x432AFF97); 162 c = II(c, d, a, b, x[k+14], S43, 0xAB9423A7); 163 b = II(b, c, d, a, x[k+5], S44, 0xFC93A039); 164 a = II(a, b, c, d, x[k+12], S41, 0x655B59C3); 165 d = II(d, a, b, c, x[k+3], S42, 0x8F0CCC92); 166 c = II(c, d, a, b, x[k+10], S43, 0xFFEFF47D); 167 b = II(b, c, d, a, x[k+1], S44, 0x85845DD1); 168 a = II(a, b, c, d, x[k+8], S41, 0x6FA87E4F); 169 d = II(d, a, b, c, x[k+15], S42, 0xFE2CE6E0); 170 c = II(c, d, a, b, x[k+6], S43, 0xA3014314); 171 b = II(b, c, d, a, x[k+13], S44, 0x4E0811A1); 172 a = II(a, b, c, d, x[k+4], S41, 0xF7537E82); 173 d = II(d, a, b, c, x[k+11], S42, 0xBD3AF235); 174 c = II(c, d, a, b, x[k+2], S43, 0x2AD7D2BB); 175 b = II(b, c, d, a, x[k+9], S44, 0xEB86D391); 176 a = addUnsigned(a, AA); 177 b = addUnsigned(b, BB); 178 c = addUnsigned(c, CC); 179 d = addUnsigned(d, DD); 180 } 181 var tempValue = wordToHex(a) + wordToHex(b) + wordToHex(c) + wordToHex(d); 182 return tempValue.toLowerCase(); 183 } 184 }); 185 })(jQuery);
