Javascript实现base64的加密解密方法

  1 function Base64() {
  2   // private property
  3   _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
  4   // 公共编码方法
  5   this.encode = function (input) {
  6     var output = "";
  7     var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
  8     var i = 0;
  9     input = _utf8_encode(input);
 10     while (i < input.length) {
 11       chr1 = input.charCodeAt(i++);
 12       chr2 = input.charCodeAt(i++);
 13       chr3 = input.charCodeAt(i++);
 14       enc1 = chr1 >> 2;
 15       enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
 16       enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
 17       enc4 = chr3 & 63;
 18       if (isNaN(chr2)) {
 19           enc3 = enc4 = 64;
 20       } else if (isNaN(chr3)) {
 21           enc4 = 64;
 22       }
 23       output = output +
 24       _keyStr.charAt(enc1) + _keyStr.charAt(enc2) +
 25       _keyStr.charAt(enc3) + _keyStr.charAt(enc4);
 26     }
 27     return output;
 28   }
 29
 30   // 公共解码方法
 31   this.decode = function (input) {
 32     var output = "";
 33     var chr1, chr2, chr3;
 34     var enc1, enc2, enc3, enc4;
 35     var i = 0;
 36     input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
 37     while (i < input.length) {
 38       enc1 = _keyStr.indexOf(input.charAt(i++));
 39       enc2 = _keyStr.indexOf(input.charAt(i++));
 40       enc3 = _keyStr.indexOf(input.charAt(i++));
 41       enc4 = _keyStr.indexOf(input.charAt(i++));
 42       chr1 = (enc1 << 2) | (enc2 >> 4);
 43       chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
 44       chr3 = ((enc3 & 3) << 6) | enc4;
 45       output = output + String.fromCharCode(chr1);
 46       if (enc3 != 64) {
 47         output = output + String.fromCharCode(chr2);
 48       }
 49       if (enc4 != 64) {
 50         output = output + String.fromCharCode(chr3);
 51       }
 52     }
 53     output = _utf8_decode(output);
 54     return output;
 55   }
 56
 57   // UTF-8编码的私有方法
 58   _utf8_encode = function (string) {
 59     string = string.replace(/\r\n/g,"\n");
 60     var utftext = "";
 61     for (var n = 0; n < string.length; n++) {
 62       var c = string.charCodeAt(n);
 63       if (c < 128) {
 64         utftext += String.fromCharCode(c);
 65       } else if((c > 127) && (c < 2048)) {
 66         utftext += String.fromCharCode((c >> 6) | 192);
 67         utftext += String.fromCharCode((c & 63) | 128);
 68       } else {
 69         utftext += String.fromCharCode((c >> 12) | 224);
 70         utftext += String.fromCharCode(((c >> 6) & 63) | 128);
 71         utftext += String.fromCharCode((c & 63) | 128);
 72       }
 73     }
 74     return utftext;
 75   }
 76
 77   // UTF-8解码的私有方法
 78   _utf8_decode = function (utftext) {
 79     var string = "";
 80     var i = 0;
 81     var c = c1 = c2 = 0;
 82     while ( i < utftext.length ) {
 83       c = utftext.charCodeAt(i);
 84       if (c < 128) {
 85         string += String.fromCharCode(c);
 86         i++;
 87       } else if((c > 191) && (c < 224)) {
 88         c2 = utftext.charCodeAt(i+1);
 89         string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
 90         i += 2;
 91       } else {
 92         c2 = utftext.charCodeAt(i+1);
 93         c3 = utftext.charCodeAt(i+2);
 94         string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
 95         i += 3;
 96       }
 97     }
 98     return string;
 99   }
100 }

加密解密方法使用：

1.加密

var str = '码云笔记mybj123';
var base = new Base64();
var result = base.encode(str);
//document.write(result);
2. 解密

var result2 = base.decode(result);
document.write(result2);