base64和Xxtea的加密和解密
数据加密是web数据安全的一种方式，前几天拿到一个base64+xxtea加密的数据，现在在这里整理一下使用的过程。首先当然是全网站找解密方法，但是最后的结果不是很理想，都不是自己想要的，这里只针对前端js的加密和解密
看代码：
``` function long2str(v, w) { var vl = v.length; var sl = v[vl - 1] & 0xffffffff; for (var i = 0; i < vl; i++) { v[i] = String.fromCharCode(v[i] & 0xff, v[i] >>> 8 & 0xff, v[i] >>> 16 & 0xff, v[i] >>> 24 & 0xff); } if (w) { return v.join('').substring(0, sl); } else { return v.join(''); } }function str2long(s, w) { var len = s.length; var v = []; for (var i = 0; i < len; i += 4) { v[i >> 2] = s.charCodeAt(i) | s.charCodeAt(i + 1) << 8 | s.charCodeAt(i + 2) << 16 | s.charCodeAt(i + 3) << 24; } if (w) { v[v.length] = len; } return v; }
function xxtea_encrypt(str, key) { if (str == "") { return ""; } var v = str2long(str, true); var k = str2long(key, false); var n = v.length - 1;
var z = v[n], y = v[0], delta = 0x9E3779B9;
var mx, e, q = Math.floor(6 + 52 / (n + 1)), sum = 0;
while (q-- > 0) {
sum = sum + delta & 0xffffffff;
e = sum >>> 2 & 3;
for (var p = 0; p < n; p++) {
y = v[p + 1];
mx = (z >>> 5 ^ y << 2) + (y >>> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z);
z = v[p] = v[p] + mx & 0xffffffff;
}
y = v[0];
mx = (z >>> 5 ^ y << 2) + (y >>> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z);
z = v[n] = v[n] + mx & 0xffffffff;
}
return long2str(v, false);
}
function xxtea_decrypt(str, key) { if (str == "") { return ""; } var v = str2long(str, false); var k = str2long(key, false); var n = v.length - 1;
var z = v[n - 1], y = v[0], delta = 0x9E3779B9;
var mx, e, q = Math.floor(6 + 52 / (n + 1)), sum = q * delta & 0xffffffff;
while (sum != 0) {
e = sum >>> 2 & 3;
for (var p = n; p > 0; p--) {
z = v[p - 1];
mx = (z >>> 5 ^ y << 2) + (y >>> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z);
y = v[p] = v[p] - mx & 0xffffffff;
}
z = v[n];
mx = (z >>> 5 ^ y << 2) + (y >>> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z);
y = v[0] = v[0] - mx & 0xffffffff;
sum = sum - delta & 0xffffffff;
}
return long2str(v, true);
}
function utf16to8(str) { var out, i, len, c;
out = [];
len = str.length;
for(i = 0; i < len; i++) {
c = str.charCodeAt(i);
if ((c >= 0x0001) && (c <= 0x007F)) {
out[i] = str.charAt(i);
} else if (c > 0x07FF) {
out[i] = String.fromCharCode(0xE0 | ((c >> 12) & 0x0F),
0x80 | ((c >> 6) & 0x3F),
0x80 | ((c >> 0) & 0x3F));
} else {
out[i] = String.fromCharCode(0xC0 | ((c >> 6) & 0x1F),
0x80 | ((c >> 0) & 0x3F));
}
}
return out.join('');
}
function utf8to16(str) { var out, i, len, c; var char2, char3;
out = [];
len = str.length;
i = 0;
while(i < len) {
c = str.charCodeAt(i++);
switch(c >> 4)
{
case 0: case 1: case 2: case 3: case 4: case 5: case 6: case 7:
// 0xxxxxxx
out[out.length] = str.charAt(i-1);
break;
case 12: case 13:
// 110x xxxx 10xx xxxx
char2 = str.charCodeAt(i++);
out[out.length] = String.fromCharCode(((c & 0x1F) << 6) | (char2 & 0x3F));
break;
case 14:
// 1110 xxxx 10xx xxxx 10xx xxxx
char2 = str.charCodeAt(i++);
char3 = str.charCodeAt(i++);
out[out.length] = String.fromCharCode(((c & 0x0F) << 12) |
((char2 & 0x3F) << 6) | ((char3 & 0x3F) << 0));
break;
}
}
return out.join('');
}
//base64解码 function decode_base64(input) { var keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
var output = "";
var chr1, chr2, chr3 = "";
var enc1, enc2, enc3, enc4 = "";
var i = 0;
// remove all characters that are not A-Z, a-z, 0-9, +, /, or =
var base64test = /[^A-Za-z0-9\+\/\=\n]/g;
if (base64test.exec(input)) {
}
input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");
do {
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);
}
chr1 = chr2 = chr3 = "";
enc1 = enc2 = enc3 = enc4 = "";
} while (i < input.length);
return output;
}
然后就是使用：
```xxtea解密函数的key参数，是数据加密的关键字，这个得着后端的程序员给你提供
