Javascript实现base64的加密解密【转】

场景

这几天使用PHP向前端传值的时候，遇到一个问题，要将代码传过去赋值。如果使用urlencode()和urldecode()函数，就会出现js无法解码的情况，因为php和js的相关函数算法不一致。于是准备使用通用的base64加密解密。

javascript base64 加密解密

  下方是base64用javascript写出来的函数和方法。

 //1.加密解密方法使用：

 //1.加密
 var str = '124中文内容';
 var base = new Base64();
 var result = base.encode(str);
 document.write(result);  

 //2.解密
 var result2 = base.decode(result);
 document.write(result2);
 //2.加密、解密算法封装：

 function Base64() {  

     // private property
     _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";  

     // public method for encoding
     this.encode = function (input) {
         var output = "";
         var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
         var i = 0;
         input = _utf8_encode(input);
         while (i < input.length) {
             chr1 = input.charCodeAt(i++);
             chr2 = input.charCodeAt(i++);
             chr3 = input.charCodeAt(i++);
             enc1 = chr1 >> 2;
             enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
             enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
             enc4 = chr3 & 63;
             if (isNaN(chr2)) {
                 enc3 = enc4 = 64;
             } else if (isNaN(chr3)) {
                 enc4 = 64;
             }
             output = output +
             _keyStr.charAt(enc1) + _keyStr.charAt(enc2) +
             _keyStr.charAt(enc3) + _keyStr.charAt(enc4);
         }
         return output;
     }  

     // public method for decoding
     this.decode = function (input) {
         var output = "";
         var chr1, chr2, chr3;
         var enc1, enc2, enc3, enc4;
         var i = 0;
         input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
         while (i < input.length) {
             enc1 = _keyStr.indexOf(input.charAt(i++));
             enc2 = _keyStr.indexOf(input.charAt(i++));
             enc3 = _keyStr.indexOf(input.charAt(i++));
             enc4 = _keyStr.indexOf(input.charAt(i++));
             chr1 = (enc1 << 2) | (enc2 >> 4);
             chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
             chr3 = ((enc3 & 3) << 6) | enc4;
             output = output + String.fromCharCode(chr1);
             if (enc3 != 64) {
                 output = output + String.fromCharCode(chr2);
             }
             if (enc4 != 64) {
                 output = output + String.fromCharCode(chr3);
             }
         }
         output = _utf8_decode(output);
         return output;
     }  

     // private method for UTF-8 encoding
     _utf8_encode = function (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;
     }  

     // private method for UTF-8 decoding
     _utf8_decode = function (utftext) {
         var string = "";
         var i = 0;
         var c = c1 = c2 = 0;
         while ( i < utftext.length ) {
             c = utftext.charCodeAt(i);
             if (c < 128) {
                 string += String.fromCharCode(c);
                 i++;
             } else if((c > 191) && (c < 224)) {
                 c2 = utftext.charCodeAt(i+1);
                 string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
                 i += 2;
             } else {
                 c2 = utftext.charCodeAt(i+1);
                 c3 = utftext.charCodeAt(i+2);
                 string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
                 i += 3;
             }
         }
         return string;
     }
 }

完全引用自

---------------------
作者：夜之寐
来源：CSDN
原文：https://blog.csdn.net/u012369749/article/details/73784897
版权声明：本文为博主原创文章，转载请附上博文链接！

其他参考

两种JavaScript的AES加密方式（可与Java相互加解密）==http://www.cnblogs.com/hellobajie/p/5726729.html