本文实例讲述了JS实现的3des+base64加密解密算法。分享给大家供大家参考，具体如下：
1. index.html：
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www.jb51.cc BASE64编码
2. DES3.js文件：
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/**
* 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 (0x1010400,0x10000,0x1010404,0x1010004,0x10404,0x4,0x400,0x1010400,0x1000404,0x1000000,0x404,0x1000400,0x10400,0x1010000,0x10004,0x1000004,0x1010004); var spfunction2 = new Array (-0x7fef7fe0,-0x7fff8000,0x8000,0x108020,0x100000,0x20,-0x7fefffe0,-0x7fff7fe0,-0x7fffffe0,-0x7fef7fe0,-0x7fef8000,-0x80000000,0x108000,0x100020,-0x7ff00000,0x8020,0x108000); var spfunction3 = new Array (0x208,0x8020200,0x8020008,0x8000200,0x20208,0x20008,0x8000008,0x20000,0x8020208,0x8020000,0x208,0x8000000,0x8,0x200,0x20200,0x8000208,0x20200); var spfunction4 = new Array (0x802001,0x2081,0x80,0x802080,0x800081,0x800001,0x2001,0x802000,0x802081,0x81,0x800080,0x1,0x2000,0x800000,0x802001,0x2080,0x802080); var spfunction5 = new Array (0x100,0x2080100,0x2080000,0x42000100,0x80000,0x100,0x40000000,0x40080100,0x2000100,0x42080000,0x80100,0x2000000,0x40080000,0x40000100,0x42080100,0x42000000,0x40000100); var spfunction6 = new Array (0x20000010,0x20400000,0x4000,0x20404010,0x10,0x400000,0x20004000,0x404010,0x20000010,0x400010,0x20000000,0x4010,0x20004010,0x404000,0x20400010,0x20404000,0x20004010); var spfunction7 = new Array (0x200000,0x4200002,0x4000802,0x800,0x200802,0x4200800,0x4200802,0x200000,0x4000002,0x2,0x4000000,0x802,0x4000800,0x200002,0x4200000,0x200800,0x200002); var spfunction8 = new Array (0x10001040,0x1000,0x40000,0x10041040,0x10000000,0x10001040,0x40,0x40040,0x10040000,0x41000,0x10041000,0x41040,0x10000040,0x10001000,0x1040,0x10040040,0x10041000); //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 (0,2,62,30,64,96,2) : new Array (94,-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); 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 (0,0x20000004,0x20010000,0x20010004,0x204,0x20000200,0x20000204,0x10200,0x10204,0x20010200,0x20010204);
var pc2bytes1 = new Array (0,0x100001,0x4000001,0x4100000,0x4100001,0x101,0x100100,0x100101,0x4000100,0x4000101,0x4100100,0x4100101);
var pc2bytes2 = new Array (0,0x808,0x1000008,0x1000800,0x1000808,0x1000808);
var pc2bytes3 = new Array (0,0x8200000,0x202000,0x8002000,0x8202000,0x220000,0x8220000,0x22000,0x222000,0x8022000,0x8222000);
var pc2bytes4 = new Array (0,0x40010,0x1010,0x41010,0x41010);
var pc2bytes5 = new Array (0,0x420,0x2000400,0x2000020,0x2000420,0x2000420);
var pc2bytes6 = new Array (0,0x10080000,0x10000002,0x80002,0x10080002,0x10080002);
var pc2bytes7 = new Array (0,0x10800,0x20000800,0x20010800,0x30000,0x20800,0x30800,0x20020000,0x20030000,0x20020800,0x20030800);
var pc2bytes8 = new Array (0,0x40002,0x2040000,0x2000002,0x2040002,0x2040002);
var pc2bytes9 = new Array (0,0x10000008,0x10000400,0x408,0x10000408,0x10000408);
var pc2bytes10 = new Array (0,0x2020,0x102000,0x102020,0x102020);
var pc2bytes11 = new Array (0,0x1000200,0x1200000,0x200200,0x1200200,0x5000000,0x4000200,0x5000200,0x5200000,0x4200200,0x5200200);
var pc2bytes12 = new Array (0,0x8001000,0x81000,0x8080000,0x8081000,0x8000010,0x8001010,0x80010,0x81010,0x8080010,0x8081010);
var pc2bytes13 = new Array (0,0x104,0x5,0x105,0x105);
//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 (0,1,0);
//other variables
var lefttemp,righttemp,m=0,n=0,temp;
for (var j=0; jterations; j++) { //either 1 or 3 iterations
var left = (key.charCodeAt(m++) << 24) | (key.charCodeAt(m++) << 16) | (key.charCodeAt(m++) << 8) | key.charCodeAt(m++);
var right = (key.charCodeAt(m++) << 24) | (key.charCodeAt(m++) << 16) | (key.charCodeAt(m++) << 8) | key.charCodeAt(m++);
temp = ((left >>> 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,24);
return btoa(des(genKey.key,input,des3iv,1));
},////3DES解密，CBC/PKCS5Padding
decrypt:function(key,24);
return des(genKey.key,atob(input),1);
}
};
* 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 (0x1010400,0x10000,0x1010404,0x1010004,0x10404,0x4,0x400,0x1010400,0x1000404,0x1000000,0x404,0x1000400,0x10400,0x1010000,0x10004,0x1000004,0x1010004); var spfunction2 = new Array (-0x7fef7fe0,-0x7fff8000,0x8000,0x108020,0x100000,0x20,-0x7fefffe0,-0x7fff7fe0,-0x7fffffe0,-0x7fef7fe0,-0x7fef8000,-0x80000000,0x108000,0x100020,-0x7ff00000,0x8020,0x108000); var spfunction3 = new Array (0x208,0x8020200,0x8020008,0x8000200,0x20208,0x20008,0x8000008,0x20000,0x8020208,0x8020000,0x208,0x8000000,0x8,0x200,0x20200,0x8000208,0x20200); var spfunction4 = new Array (0x802001,0x2081,0x80,0x802080,0x800081,0x800001,0x2001,0x802000,0x802081,0x81,0x800080,0x1,0x2000,0x800000,0x802001,0x2080,0x802080); var spfunction5 = new Array (0x100,0x2080100,0x2080000,0x42000100,0x80000,0x100,0x40000000,0x40080100,0x2000100,0x42080000,0x80100,0x2000000,0x40080000,0x40000100,0x42080100,0x42000000,0x40000100); var spfunction6 = new Array (0x20000010,0x20400000,0x4000,0x20404010,0x10,0x400000,0x20004000,0x404010,0x20000010,0x400010,0x20000000,0x4010,0x20004010,0x404000,0x20400010,0x20404000,0x20004010); var spfunction7 = new Array (0x200000,0x4200002,0x4000802,0x800,0x200802,0x4200800,0x4200802,0x200000,0x4000002,0x2,0x4000000,0x802,0x4000800,0x200002,0x4200000,0x200800,0x200002); var spfunction8 = new Array (0x10001040,0x1000,0x40000,0x10041040,0x10000000,0x10001040,0x40,0x40040,0x10040000,0x41000,0x10041000,0x41040,0x10000040,0x10001000,0x1040,0x10040040,0x10041000); //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 (0,2,62,30,64,96,2) : new Array (94,-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); 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
3. Base64.js文件：
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;
}
};
运行结果：
PS：关于加密解密感兴趣的朋友还可以参考本站在线工具：
文字在线加密解密工具（包含AES、DES、RC4等）：
在线编码转换工具(utf-8/utf-32/Punycode/Base64)：
BASE64
编码解码工具：在线MD5/hash/SHA-1/SHA-2/SHA-256/SHA-512/SHA-3/RIPEMD-160加密工具：
》希望本文所述对大家JavaScript程序设计有所帮助。
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