js base64加密与C#后台base64解密

js代码

   function encode64(input) {
         var output = "";
         var base = new Base64();
         var output = base.encode(input);
         return output;
     }

     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 = ;
             input = _utf8_encode(input);
             while (i < input.length) {
                 chr1 = input.charCodeAt(i++);
                 chr2 = input.charCodeAt(i++);
                 chr3 = input.charCodeAt(i++);
                 enc1 = chr1 >> ;
                 enc2 = ((chr1 & ) << ) | (chr2 >> );
                 enc3 = ((chr2 & ) << ) | (chr3 >> );
                 enc4 = chr3 & ;
                 if (isNaN(chr2)) {
                     enc3 = enc4 = ;
                 } else if (isNaN(chr3)) {
                     enc4 = ;
                 }
                 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 = ;
             input = input.replace(/[^A-Za-z0-\+\/\=]/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 << ) | (enc2 >> );
                 chr2 = ((enc2 & ) << ) | (enc3 >> );
                 chr3 = ((enc3 & ) << ) | enc4;
                 output = output + String.fromCharCode(chr1);
                 if (enc3 != ) {
                     output = output + String.fromCharCode(chr2);
                 }
                 if (enc4 != ) {
                     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 = ; n < string.length; n++) {
                 var c = string.charCodeAt(n);
                 if (c < ) {
                     utftext += String.fromCharCode(c);
                 } else if ((c > ) && (c < )) {
                     utftext += String.fromCharCode((c >> ) | );
                     utftext += String.fromCharCode((c & ) | );
                 } else {
                     utftext += String.fromCharCode((c >> ) | );
                     utftext += String.fromCharCode(((c >> ) & ) | );
                     utftext += String.fromCharCode((c & ) | );
                 }

             }
             return utftext;
         }

         // private method for UTF-8 decoding
         _utf8_decode = function (utftext) {
             var string = "";
             var i = ;
             var c = c1 = c2 = ;
             while (i < utftext.length) {
                 c = utftext.charCodeAt(i);
                 if (c < ) {
                     string += String.fromCharCode(c);
                     i++;
                 } else if ((c > ) && (c < )) {
                     c2 = utftext.charCodeAt(i + );
                     string += String.fromCharCode(((c & ) << ) | (c2 & ));
                     i += ;
                 } else {
                     c2 = utftext.charCodeAt(i + );
                     c3 = utftext.charCodeAt(i + );
                     string += String.fromCharCode(((c & ) << ) | ((c2 & ) << ) | (c3 & ));
                     i += ;
                 }
             }
             return string;
         }
     }

   /// <summary>
         /// base64解密
         /// </summary>
         /// <param name="encode">编码，与js一致</param>
         /// <param name="result">加密源字符串</param>
         /// <returns></returns>
         public static string DecodeBase64(Encoding encode, string result)
         {
             string decode = "";
             byte[] bytes = Convert.FromBase64String(result);
             try
             {
                 decode = encode.GetString(bytes);
             }
             catch
             {
                 decode = result;
             }
             return decode;
         }