How to use JS to implement 3des+base64 encryption and decryption algorithm

/** * DES 加密算法 * * 该函数接受一个 8 字节字符串作为普通 DES 算法的密钥（也就是 64 位，但是算法只使用 56 位），或者接受一个 24 字节字符串作为 3DES * 算法的密钥；第二个参数是要加密或解密的信息字符串；第三个布尔值参数用来说明信息是加密还是解密；接下来的可选参数 mode 如果是 0 表示 ECB * 模式，1 表示 CBC 模式，默认是 ECB 模式；最后一个可选项是一个 8 字节的输入向量字符串（在 ECB 模式下不使用）。返回的密文是字符串。 * * 参数： 
 * key: 8字节字符串作为普通 DES 算法的密钥,或 24 字节字符串作为 3DES 
 * message： 加密或解密的信息字符串
 * encrypt: 布尔值参数用来说明信息是加密还是解密
 * mode: 1:CBC模式，0:ECB模式(默认)
 * iv:
 * padding: 可选项, 8字节的输入向量字符串（在 ECB 模式下不使用） */ //this takes the key, the message, and whether to encrypt or decrypt function des (key, message, encrypt, mode, iv, padding) { if(encrypt) //如果是加密的话，首先转换编码 message = unescape(encodeURIComponent(message)); //declaring this locally speeds things up a bit var spfunction1 = new Array (0x1010400,0,0x10000,0x1010404,0x1010004,0x10404,0x4,0x10000,0x400,0x1010400,0x1010404,0x400,0x1000404,0x1010004,0x1000000,0x4,0x404,0x1000400,0x1000400,0x10400,0x10400,0x1010000,0x1010000,0x1000404,0x10004,0x1000004,0x1000004,0x10004,0,0x404,0x10404,0x1000000,0x10000,0x1010404,0x4,0x1010000,0x1010400,0x1000000,0x1000000,0x400,0x1010004,0x10000,0x10400,0x1000004,0x400,0x4,0x1000404,0x10404,0x1010404,0x10004,0x1010000,0x1000404,0x1000004,0x404,0x10404,0x1010400,0x404,0x1000400,0x1000400,0,0x10004,0x10400,0,0x1010004); var spfunction2 = new Array (-0x7fef7fe0,-0x7fff8000,0x8000,0x108020,0x100000,0x20,-0x7fefffe0,-0x7fff7fe0,-0x7fffffe0,-0x7fef7fe0,-0x7fef8000,-0x80000000,-0x7fff8000,0x100000,0x20,-0x7fefffe0,0x108000,0x100020,-0x7fff7fe0,0,-0x80000000,0x8000,0x108020,-0x7ff00000,0x100020,-0x7fffffe0,0,0x108000,0x8020,-0x7fef8000,-0x7ff00000,0x8020,0,0x108020,-0x7fefffe0,0x100000,-0x7fff7fe0,-0x7ff00000,-0x7fef8000,0x8000,-0x7ff00000,-0x7fff8000,0x20,-0x7fef7fe0,0x108020,0x20,0x8000,-0x80000000,0x8020,-0x7fef8000,0x100000,-0x7fffffe0,0x100020,-0x7fff7fe0,-0x7fffffe0,0x100020,0x108000,0,-0x7fff8000,0x8020,-0x80000000,-0x7fefffe0,-0x7fef7fe0,0x108000); var spfunction3 = new Array (0x208,0x8020200,0,0x8020008,0x8000200,0,0x20208,0x8000200,0x20008,0x8000008,0x8000008,0x20000,0x8020208,0x20008,0x8020000,0x208,0x8000000,0x8,0x8020200,0x200,0x20200,0x8020000,0x8020008,0x20208,0x8000208,0x20200,0x20000,0x8000208,0x8,0x8020208,0x200,0x8000000,0x8020200,0x8000000,0x20008,0x208,0x20000,0x8020200,0x8000200,0,0x200,0x20008,0x8020208,0x8000200,0x8000008,0x200,0,0x8020008,0x8000208,0x20000,0x8000000,0x8020208,0x8,0x20208,0x20200,0x8000008,0x8020000,0x8000208,0x208,0x8020000,0x20208,0x8,0x8020008,0x20200); var spfunction4 = new Array (0x802001,0x2081,0x2081,0x80,0x802080,0x800081,0x800001,0x2001,0,0x802000,0x802000,0x802081,0x81,0,0x800080,0x800001,0x1,0x2000,0x800000,0x802001,0x80,0x800000,0x2001,0x2080,0x800081,0x1,0x2080,0x800080,0x2000,0x802080,0x802081,0x81,0x800080,0x800001,0x802000,0x802081,0x81,0,0,0x802000,0x2080,0x800080,0x800081,0x1,0x802001,0x2081,0x2081,0x80,0x802081,0x81,0x1,0x2000,0x800001,0x2001,0x802080,0x800081,0x2001,0x2080,0x800000,0x802001,0x80,0x800000,0x2000,0x802080); var spfunction5 = new Array (0x100,0x2080100,0x2080000,0x42000100,0x80000,0x100,0x40000000,0x2080000,0x40080100,0x80000,0x2000100,0x40080100,0x42000100,0x42080000,0x80100,0x40000000,0x2000000,0x40080000,0x40080000,0,0x40000100,0x42080100,0x42080100,0x2000100,0x42080000,0x40000100,0,0x42000000,0x2080100,0x2000000,0x42000000,0x80100,0x80000,0x42000100,0x100,0x2000000,0x40000000,0x2080000,0x42000100,0x40080100,0x2000100,0x40000000,0x42080000,0x2080100,0x40080100,0x100,0x2000000,0x42080000,0x42080100,0x80100,0x42000000,0x42080100,0x2080000,0,0x40080000,0x42000000,0x80100,0x2000100,0x40000100,0x80000,0,0x40080000,0x2080100,0x40000100); var spfunction6 = new Array (0x20000010,0x20400000,0x4000,0x20404010,0x20400000,0x10,0x20404010,0x400000,0x20004000,0x404010,0x400000,0x20000010,0x400010,0x20004000,0x20000000,0x4010,0,0x400010,0x20004010,0x4000,0x404000,0x20004010,0x10,0x20400010,0x20400010,0,0x404010,0x20404000,0x4010,0x404000,0x20404000,0x20000000,0x20004000,0x10,0x20400010,0x404000,0x20404010,0x400000,0x4010,0x20000010,0x400000,0x20004000,0x20000000,0x4010,0x20000010,0x20404010,0x404000,0x20400000,0x404010,0x20404000,0,0x20400010,0x10,0x4000,0x20400000,0x404010,0x4000,0x400010,0x20004010,0,0x20404000,0x20000000,0x400010,0x20004010); var spfunction7 = new Array (0x200000,0x4200002,0x4000802,0,0x800,0x4000802,0x200802,0x4200800,0x4200802,0x200000,0,0x4000002,0x2,0x4000000,0x4200002,0x802,0x4000800,0x200802,0x200002,0x4000800,0x4000002,0x4200000,0x4200800,0x200002,0x4200000,0x800,0x802,0x4200802,0x200800,0x2,0x4000000,0x200800,0x4000000,0x200800,0x200000,0x4000802,0x4000802,0x4200002,0x4200002,0x2,0x200002,0x4000000,0x4000800,0x200000,0x4200800,0x802,0x200802,0x4200800,0x802,0x4000002,0x4200802,0x4200000,0x200800,0,0x2,0x4200802,0,0x200802,0x4200000,0x800,0x4000002,0x4000800,0x800,0x200002); var spfunction8 = new Array (0x10001040,0x1000,0x40000,0x10041040,0x10000000,0x10001040,0x40,0x10000000,0x40040,0x10040000,0x10041040,0x41000,0x10041000,0x41040,0x1000,0x40,0x10040000,0x10000040,0x10001000,0x1040,0x41000,0x40040,0x10040040,0x10041000,0x1040,0,0,0x10040040,0x10000040,0x10001000,0x41040,0x40000,0x41040,0x40000,0x10041000,0x1000,0x40,0x10040040,0x1000,0x41040,0x10001000,0x40,0x10000040,0x10040000,0x10040040,0x10000000,0x40000,0x10001040,0,0x10041040,0x40040,0x10000040,0x10040000,0x10001000,0x10001040,0,0x10041040,0x41000,0x41000,0x1040,0x1040,0x40040,0x10000000,0x10041000); //create the 16 or 48 subkeys we will need var keys = des_createKeys (key); var m=0, i, j, temp, temp2, right1, right2, left, right, looping; var cbcleft, cbcleft2, cbcright, cbcright2 var endloop, loopinc; var len = message.length; var chunk = 0; //set up the loops for single and triple des var iterations = keys.length == 32 ? 3 : 9; //single or triple des if (iterations == 3) {looping = encrypt ? new Array (0, 32, 2) : new Array (30, -2, -2);} else {looping = encrypt ? new Array (0, 32, 2, 62, 30, -2, 64, 96, 2) : new Array (94, 62, -2, 32, 64, 2, 30, -2, -2);} //pad the message depending on the padding parameter if (padding == 2) message += " "; //pad the message with spaces else if (padding == 1) { if(encrypt) { temp = 8-(len%8); message += String.fromCharCode(temp,temp,temp,temp,temp,temp,temp,temp); if (temp===8) len+=8; } } //PKCS7 padding else if (!padding) message += "\0\0\0\0\0\0\0\0"; //pad the message out with null bytes //store the result here var result = ""; var tempresult = ""; if (mode == 1) { //CBC mode cbcleft = (iv.charCodeAt(m++) << 24) | (iv.charCodeAt(m++) << 16) | (iv.charCodeAt(m++) << 8) | iv.charCodeAt(m++); cbcright = (iv.charCodeAt(m++) << 24) | (iv.charCodeAt(m++) << 16) | (iv.charCodeAt(m++) << 8) | iv.charCodeAt(m++); m=0; } //loop through each 64 bit chunk of the message while (m < len) { left = (message.charCodeAt(m++) << 24) | (message.charCodeAt(m++) << 16) | (message.charCodeAt(m++) << 8) | message.charCodeAt(m++); right = (message.charCodeAt(m++) << 24) | (message.charCodeAt(m++) << 16) | (message.charCodeAt(m++) << 8) | message.charCodeAt(m++); //for Cipher Block Chaining mode, xor the message with the previous result if (mode == 1) {if (encrypt) {left ^= cbcleft; right ^= cbcright;} else {cbcleft2 = cbcleft; cbcright2 = cbcright; cbcleft = left; cbcright = right;}} //first each 64 but chunk of the message must be permuted according to IP temp = ((left >>> 4) ^ right) & 0x0f0f0f0f; right ^= temp; left ^= (temp << 4); temp = ((left >>> 16) ^ right) & 0x0000ffff; right ^= temp; left ^= (temp << 16); temp = ((right >>> 2) ^ left) & 0x33333333; left ^= temp; right ^= (temp << 2); temp = ((right >>> 8) ^ left) & 0x00ff00ff; left ^= temp; right ^= (temp << 8); temp = ((left >>> 1) ^ right) & 0x55555555; right ^= temp; left ^= (temp << 1); left = ((left << 1) | (left >>> 31)); right = ((right << 1) | (right >>> 31)); //do this either 1 or 3 times for each chunk of the message for (j=0; j>> 4) | (right << 28)) ^ keys[i+1]; //the result is attained by passing these bytes through the S selection functions temp = left; left = right; right = temp ^ (spfunction2[(right1 >>> 24) & 0x3f] | spfunction4[(right1 >>> 16) & 0x3f] | spfunction6[(right1 >>> 8) & 0x3f] | spfunction8[right1 & 0x3f] | spfunction1[(right2 >>> 24) & 0x3f] | spfunction3[(right2 >>> 16) & 0x3f] | spfunction5[(right2 >>> 8) & 0x3f] | spfunction7[right2 & 0x3f]); } temp = left; left = right; right = temp; //unreverse left and right } //for either 1 or 3 iterations //move then each one bit to the right left = ((left >>> 1) | (left << 31)); right = ((right >>> 1) | (right << 31)); //now perform IP-1, which is IP in the opposite direction temp = ((left >>> 1) ^ right) & 0x55555555; right ^= temp; left ^= (temp << 1); temp = ((right >>> 8) ^ left) & 0x00ff00ff; left ^= temp; right ^= (temp << 8); temp = ((right >>> 2) ^ left) & 0x33333333; left ^= temp; right ^= (temp << 2); temp = ((left >>> 16) ^ right) & 0x0000ffff; right ^= temp; left ^= (temp << 16); temp = ((left >>> 4) ^ right) & 0x0f0f0f0f; right ^= temp; left ^= (temp << 4); //for Cipher Block Chaining mode, xor the message with the previous result if (mode == 1) {if (encrypt) {cbcleft = left; cbcright = right;} else {left ^= cbcleft2; right ^= cbcright2;}} tempresult += String.fromCharCode ((left>>>24), ((left>>>16) & 0xff), ((left>>>8) & 0xff), (left & 0xff), (right>>>24), ((right>>>16) & 0xff), ((right>>>8) & 0xff), (right & 0xff)); chunk += 8; if (chunk == 512) {result += tempresult; tempresult = ""; chunk = 0;} } //for every 8 characters, or 64 bits in the message //return the result as an array result += tempresult; result = result.replace(/\0*$/g, ""); if(!encrypt ) { //如果是解密的话，解密结束后对PKCS7 padding进行解码，并转换成utf-8编码 if(padding === 1) { //PKCS7 padding解码 var len = result.length, paddingChars = 0; len && (paddingChars = result.charCodeAt(len-1)); (paddingChars <= 8) && (result = result.substring(0, len - paddingChars)); } //转换成UTF-8编码 result = decodeURIComponent(escape(result)); } return result; } //end of des //des_createKeys //this takes as input a 64 bit key (even though only 56 bits are used) //as an array of 2 integers, and returns 16 48 bit keys function des_createKeys (key) { //declaring this locally speeds things up a bit var pc2bytes0 = new Array (0,0x4,0x20000000,0x20000004,0x10000,0x10004,0x20010000,0x20010004,0x200,0x204,0x20000200,0x20000204,0x10200,0x10204,0x20010200,0x20010204); var pc2bytes1 = new Array (0,0x1,0x100000,0x100001,0x4000000,0x4000001,0x4100000,0x4100001,0x100,0x101,0x100100,0x100101,0x4000100,0x4000101,0x4100100,0x4100101); var pc2bytes2 = new Array (0,0x8,0x800,0x808,0x1000000,0x1000008,0x1000800,0x1000808,0,0x8,0x800,0x808,0x1000000,0x1000008,0x1000800,0x1000808); var pc2bytes3 = new Array (0,0x200000,0x8000000,0x8200000,0x2000,0x202000,0x8002000,0x8202000,0x20000,0x220000,0x8020000,0x8220000,0x22000,0x222000,0x8022000,0x8222000); var pc2bytes4 = new Array (0,0x40000,0x10,0x40010,0,0x40000,0x10,0x40010,0x1000,0x41000,0x1010,0x41010,0x1000,0x41000,0x1010,0x41010); var pc2bytes5 = new Array (0,0x400,0x20,0x420,0,0x400,0x20,0x420,0x2000000,0x2000400,0x2000020,0x2000420,0x2000000,0x2000400,0x2000020,0x2000420); var pc2bytes6 = new Array (0,0x10000000,0x80000,0x10080000,0x2,0x10000002,0x80002,0x10080002,0,0x10000000,0x80000,0x10080000,0x2,0x10000002,0x80002,0x10080002); var pc2bytes7 = new Array (0,0x10000,0x800,0x10800,0x20000000,0x20010000,0x20000800,0x20010800,0x20000,0x30000,0x20800,0x30800,0x20020000,0x20030000,0x20020800,0x20030800); var pc2bytes8 = new Array (0,0x40000,0,0x40000,0x2,0x40002,0x2,0x40002,0x2000000,0x2040000,0x2000000,0x2040000,0x2000002,0x2040002,0x2000002,0x2040002); var pc2bytes9 = new Array (0,0x10000000,0x8,0x10000008,0,0x10000000,0x8,0x10000008,0x400,0x10000400,0x408,0x10000408,0x400,0x10000400,0x408,0x10000408); var pc2bytes10 = new Array (0,0x20,0,0x20,0x100000,0x100020,0x100000,0x100020,0x2000,0x2020,0x2000,0x2020,0x102000,0x102020,0x102000,0x102020); var pc2bytes11 = new Array (0,0x1000000,0x200,0x1000200,0x200000,0x1200000,0x200200,0x1200200,0x4000000,0x5000000,0x4000200,0x5000200,0x4200000,0x5200000,0x4200200,0x5200200); var pc2bytes12 = new Array (0,0x1000,0x8000000,0x8001000,0x80000,0x81000,0x8080000,0x8081000,0x10,0x1010,0x8000010,0x8001010,0x80010,0x81010,0x8080010,0x8081010); var pc2bytes13 = new Array (0,0x4,0x100,0x104,0,0x4,0x100,0x104,0x1,0x5,0x101,0x105,0x1,0x5,0x101,0x105); //how many iterations (1 for des, 3 for triple des) var iterations = key.length > 8 ? 3 : 1; //changed by Paul 16/6/2007 to use Triple DES for 9+ byte keys //stores the return keys var keys = new Array (32 * iterations); //now define the left shifts which need to be done var shifts = new Array (0, 0, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 0); //other variables var lefttemp, righttemp, m=0, n=0, temp; for (var j=0; j>> 4) ^ right) & 0x0f0f0f0f; right ^= temp; left ^= (temp << 4); temp = ((right >>> -16) ^ left) & 0x0000ffff; left ^= temp; right ^= (temp << -16); temp = ((left >>> 2) ^ right) & 0x33333333; right ^= temp; left ^= (temp << 2); temp = ((right >>> -16) ^ left) & 0x0000ffff; left ^= temp; right ^= (temp << -16); temp = ((left >>> 1) ^ right) & 0x55555555; right ^= temp; left ^= (temp << 1); temp = ((right >>> 8) ^ left) & 0x00ff00ff; left ^= temp; right ^= (temp << 8); temp = ((left >>> 1) ^ right) & 0x55555555; right ^= temp; left ^= (temp << 1); //the right side needs to be shifted and to get the last four bits of the left side temp = (left << 8) | ((right >>> 20) & 0x000000f0); //left needs to be put upside down left = (right << 24) | ((right << 8) & 0xff0000) | ((right >>> 8) & 0xff00) | ((right >>> 24) & 0xf0); right = temp; //now go through and perform these shifts on the left and right keys for (var i=0; i < shifts.length; i++) { //shift the keys either one or two bits to the left if (shifts[i]) {left = (left << 2) | (left >>> 26); right = (right << 2) | (right >>> 26);} else {left = (left << 1) | (left >>> 27); right = (right << 1) | (right >>> 27);} left &= -0xf; right &= -0xf; //now apply PC-2, in such a way that E is easier when encrypting or decrypting //this conversion will look like PC-2 except only the last 6 bits of each byte are used //rather than 48 consecutive bits and the order of lines will be according to //how the S selection functions will be applied: S2, S4, S6, S8, S1, S3, S5, S7 lefttemp = pc2bytes0[left >>> 28] | pc2bytes1[(left >>> 24) & 0xf] | pc2bytes2[(left >>> 20) & 0xf] | pc2bytes3[(left >>> 16) & 0xf] | pc2bytes4[(left >>> 12) & 0xf] | pc2bytes5[(left >>> 8) & 0xf] | pc2bytes6[(left >>> 4) & 0xf]; righttemp = pc2bytes7[right >>> 28] | pc2bytes8[(right >>> 24) & 0xf] | pc2bytes9[(right >>> 20) & 0xf] | pc2bytes10[(right >>> 16) & 0xf] | pc2bytes11[(right >>> 12) & 0xf] | pc2bytes12[(right >>> 8) & 0xf] | pc2bytes13[(right >>> 4) & 0xf]; temp = ((righttemp >>> 16) ^ lefttemp) & 0x0000ffff; keys[n++] = lefttemp ^ temp; keys[n++] = righttemp ^ (temp << 16); } } //for each iterations //return the keys we've created return keys; } //end of des_createKeys function genkey(key, start, end) { //8 byte / 64 bit Key (DES) or 192 bit Key return {key:pad(key.slice(start, end)),vector: 1}; } function pad(key) { for (var i = key.length; i<24; i++) { key+="0"; } return key; } var des3iv = '12345678'; var DES3 = { //3DES加密，CBC/PKCS5Padding encrypt:function(key,input){ var genKey = genkey(key, 0, 24); return btoa(des(genKey.key, input, 1, 1, des3iv, 1)); }, ////3DES解密，CBC/PKCS5Padding decrypt:function(key,input){ var genKey = genkey(key, 0, 24); return des(genKey.key, atob(input), 0, 1, des3iv, 1); } };

/** *create by 2014年7月9日 http://javascript.css-js.com/ *BASE64 Encode and Decode By UTF-8 unicode *可以和java的BASE64编码和解码互相转化 */ var BASE64_MAPPING = [ 'A','B','C','D','E','F','G','H', 'I','J','K','L','M','N','O','P', 'Q','R','S','T','U','V','W','X', 'Y','Z','a','b','c','d','e','f', 'g','h','i','j','k','l','m','n', 'o','p','q','r','s','t','u','v', 'w','x','y','z','0','1','2','3', '4','5','6','7','8','9','+','/' ]; /** *ascii convert to binary */ var _toBinary = function(ascii){ var binary = new Array(); while(ascii > 0){ var b = ascii%2; ascii = Math.floor(ascii/2); binary.push(b); } /* var len = binary.length; if(6-len > 0){ for(var i = 6-len ; i > 0 ; --i){ binary.push(0); } }*/ binary.reverse(); return binary; }; /** *binary convert to decimal */ var _toDecimal = function(binary){ var dec = 0; var p = 0; for(var i = binary.length-1 ; i >= 0 ; --i){ var b = binary[i]; if(b == 1){ dec += Math.pow(2 , p); } ++p; } return dec; }; /** *unicode convert to utf-8 */ var _toUTF8Binary = function(c , binaryArray){ var mustLen = (8-(c+1)) + ((c-1)*6); var fatLen = binaryArray.length; var diff = mustLen - fatLen; while(--diff >= 0){ binaryArray.unshift(0); } var binary = []; var _c = c; while(--_c >= 0){ binary.push(1); } binary.push(0); var i = 0 , len = 8 - (c+1); for(; i < len ; ++i){ binary.push(binaryArray[i]); } for(var j = 0 ; j < c-1 ; ++j){ binary.push(1); binary.push(0); var sum = 6; while(--sum >= 0){ binary.push(binaryArray[i++]); } } return binary; }; var BASE64 = { /** *BASE64 Encode */ encoder:function(str){ var base64_Index = []; var binaryArray = []; for(var i = 0 , len = str.length ; i < len ; ++i){ var unicode = str.charCodeAt(i); var _tmpBinary = _toBinary(unicode); if(unicode < 0x80){ var _tmpdiff = 8 - _tmpBinary.length; while(--_tmpdiff >= 0){ _tmpBinary.unshift(0); } binaryArray = binaryArray.concat(_tmpBinary); }else if(unicode >= 0x80 && unicode <= 0x7FF){ binaryArray = binaryArray.concat(_toUTF8Binary(2 , _tmpBinary)); }else if(unicode >= 0x800 && unicode <= 0xFFFF){//UTF-8 3byte binaryArray = binaryArray.concat(_toUTF8Binary(3 , _tmpBinary)); }else if(unicode >= 0x10000 && unicode <= 0x1FFFFF){//UTF-8 4byte binaryArray = binaryArray.concat(_toUTF8Binary(4 , _tmpBinary)); }else if(unicode >= 0x200000 && unicode <= 0x3FFFFFF){//UTF-8 5byte binaryArray = binaryArray.concat(_toUTF8Binary(5 , _tmpBinary)); }else if(unicode >= 4000000 && unicode <= 0x7FFFFFFF){//UTF-8 6byte binaryArray = binaryArray.concat(_toUTF8Binary(6 , _tmpBinary)); } } var extra_Zero_Count = 0; for(var i = 0 , len = binaryArray.length ; i < len ; i+=6){ var diff = (i+6)-len; if(diff == 2){ extra_Zero_Count = 2; }else if(diff == 4){ extra_Zero_Count = 4; } //if(extra_Zero_Count > 0){ // len += extra_Zero_Count+1; //} var _tmpExtra_Zero_Count = extra_Zero_Count; while(--_tmpExtra_Zero_Count >= 0){ binaryArray.push(0); } base64_Index.push(_toDecimal(binaryArray.slice(i , i+6))); } var base64 = ''; for(var i = 0 , len = base64_Index.length ; i < len ; ++i){ base64 += BASE64_MAPPING[base64_Index[i]]; } for(var i = 0 , len = extra_Zero_Count/2 ; i < len ; ++i){ base64 += '='; } return base64; }, /** *BASE64 Decode for UTF-8 */ decoder : function(_base64Str){ var _len = _base64Str.length; var extra_Zero_Count = 0; /** *计算在进行BASE64编码的时候，补了几个0 */ if(_base64Str.charAt(_len-1) == '='){ //alert(_base64Str.charAt(_len-1)); //alert(_base64Str.charAt(_len-2)); if(_base64Str.charAt(_len-2) == '='){//两个等号说明补了4个0 extra_Zero_Count = 4; _base64Str = _base64Str.substring(0 , _len-2); }else{//一个等号说明补了2个0 extra_Zero_Count = 2; _base64Str = _base64Str.substring(0 , _len - 1); } } var binaryArray = []; for(var i = 0 , len = _base64Str.length; i < len ; ++i){ var c = _base64Str.charAt(i); for(var j = 0 , size = BASE64_MAPPING.length ; j < size ; ++j){ if(c == BASE64_MAPPING[j]){ var _tmp = _toBinary(j); /*不足6位的补0*/ var _tmpLen = _tmp.length; if(6-_tmpLen > 0){ for(var k = 6-_tmpLen ; k > 0 ; --k){ _tmp.unshift(0); } } binaryArray = binaryArray.concat(_tmp); break; } } } if(extra_Zero_Count > 0){ binaryArray = binaryArray.slice(0 , binaryArray.length - extra_Zero_Count); } var unicode = []; var unicodeBinary = []; for(var i = 0 , len = binaryArray.length ; i < len ; ){ if(binaryArray[i] == 0){ unicode=unicode.concat(_toDecimal(binaryArray.slice(i,i+8))); i += 8; }else{ var sum = 0; while(i < len){ if(binaryArray[i] == 1){ ++sum; }else{ break; } ++i; } unicodeBinary = unicodeBinary.concat(binaryArray.slice(i+1 , i+8-sum)); i += 8 - sum; while(sum > 1){ unicodeBinary = unicodeBinary.concat(binaryArray.slice(i+2 , i+8)); i += 8; --sum; } unicode = unicode.concat(_toDecimal(unicodeBinary)); unicodeBinary = []; } } //---------直接转换为结果 var strResult = ''; for(var i = 0 , len = unicode.length ; i < len ;++i){ strResult += String.fromCharCode(unicode[i]); } return strResult; } };