异或的符号是^。按位异或运算, 对等长二进制模式按位或二进制数的每一位执行逻辑按位异或操作. 操作的结果是如果某位不同则该位为1, 否则该位为0.
xor运算的逆运算是它本身,也就是说两次异或同一个数最后结果不变,即(a xor b) xor b = a。xor运算可以用于简单的加密,比如我想对我MM说1314520,但怕别人知道,于是双方约定拿我的生日19880516作为密钥。1314520 xor 19880516 = 20665500,我就把20665500告诉MM。MM再次计算20665500 xor 19880516的值,得到1314520,于是她就明白了我的企图。
相同位不同则为1,相同则为0。
00101
11100
(^或者xor)
----------------
11001
运算结果
x
function encodeUTF8(s) {
var i, r = [], c, x;
for (i = 0; i < s.length; i++)
if ((c = s.charCodeAt(i)) < 0x80) r.push(c);
else if (c < 0x800) r.push(0xC0 + (c >> 6 & 0x1F), 0x80 + (c & 0x3F));
else {
if ((x = c ^ 0xD800) >> 10 == 0) //对四字节UTF-16转换为Unicode
c = (x > 18 & 0x7), 0x80 + (c >> 12 & 0x3F));
else r.push(0xE0 + (c >> 12 & 0xF));
r.push(0x80 + (c >> 6 & 0x3F), 0x80 + (c & 0x3F));
};
return r;
}
// 字符串加密成 hex 字符串
function sha1(s) {
var data = new Uint8Array(encodeUTF8(s))
var i, j, t;
var l = ((data.length + 8) >>> 6 2;
enc2 = ((chr1 & 3) > 4);
enc3 = ((chr2 & 15) > 6);
enc4 = chr3 & 63;
if (isNaN(chr2))
{
enc3 = enc4 = 64;
}
else if (isNaN(chr3))
{
enc4 = 64;
}
output = output +
this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) +
this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);
} // Whend
return output;
} // End Function encode
// public method for decoding
,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 = this._keyStr.indexOf(input.charAt(i++));
enc2 = this._keyStr.indexOf(input.charAt(i++));
enc3 = this._keyStr.indexOf(input.charAt(i++));
enc4 = this._keyStr.indexOf(input.charAt(i++));
chr1 = (enc1 > 4);
chr2 = ((enc2 & 15) > 2);
chr3 = ((enc3 & 3) 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);
}
} // Next n
return utftext;
} // End Function _utf8_encode
// private method for UTF-8 decoding
,_utf8_decode: function (utftext)
{
var string = "";
var i = 0;
var c, c1, c2, c3;
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) |