关于加密解密 Base64 and URL and Hex Encoding and Decoding
今天想换一下Discuz论坛的风格，谁知下载风格文件后，发现竟然是通过Base64加密过的
小林给推荐了个解密的页面，提取出代码如下：
代码如下:
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>Base64 and URL and Hex Encoding and Decoding</title>
<meta name="description" content="Encodes or decodes data in Base64 or URL encoding using client side JavaScript" />
<meta name="keywords" content="base64, base 64, urlencode, urldecode, hexencode, hex encode, hexdecode hex decode, javascript base64, javascript base 64, javascript urlencode, javascript urldecode, javascript hexencode, javascript hexdecode" />
<link rel="shortcut icon" href="http://ostermiller.org/favicon.ico" type="image/x-icon" />
<script language=javascript type="text/javascript">
<!--
function urlDecode(str){
str=str.replace(new RegExp('\\+','g'),' ');
return unescape(str);
}
function urlEncode(str){
str=escape(str);
str=str.replace(new RegExp('\\+','g'),'%2B');
return str.replace(new RegExp('%20','g'),'+');
}
var END_OF_INPUT = -1;
var base64Chars = new Array(
'A','B','C','D','E','F','G','H',
'I','J','K','L','M','N','O','P',
'Q','R','S','T','U','V','W','X',
'Y','Z','a','b','c','d','e','f',
'g','h','i','j','k','l','m','n',
'o','p','q','r','s','t','u','v',
'w','x','y','z','0','1','2','3',
'4','5','6','7','8','9','+','/'
);
var reverseBase64Chars = new Array();
for (var i=0; i < base64Chars.length; i++){
reverseBase64Chars[base64Chars[i]] = i;
}
var base64Str;
var base64Count;
function setBase64Str(str){
base64Str = str;
base64Count = 0;
}
function readBase64(){
if (!base64Str) return END_OF_INPUT;
if (base64Count >= base64Str.length) return END_OF_INPUT;
var c = base64Str.charCodeAt(base64Count) & 0xff;
base64Count++;
return c;
}
function encodeBase64(str){
setBase64Str(str);
var result = '';
var inBuffer = new Array(3);
var lineCount = 0;
var done = false;
while (!done && (inBuffer[0] = readBase64()) != END_OF_INPUT){
inBuffer[1] = readBase64();
inBuffer[2] = readBase64();
result += (base64Chars[ inBuffer[0] >> 2 ]);
if (inBuffer[1] != END_OF_INPUT){
result += (base64Chars [(( inBuffer[0] << 4 ) & 0x30) | (inBuffer[1] >> 4) ]);
if (inBuffer[2] != END_OF_INPUT){
result += (base64Chars [((inBuffer[1] << 2) & 0x3c) | (inBuffer[2] >> 6) ]);
result += (base64Chars [inBuffer[2] & 0x3F]);
} else {
result += (base64Chars [((inBuffer[1] << 2) & 0x3c)]);
result += ('=');
done = true;
}
} else {
result += (base64Chars [(( inBuffer[0] << 4 ) & 0x30)]);
result += ('=');
result += ('=');
done = true;
}
lineCount += 4;
if (lineCount >= 76){
result += ('\n');
lineCount = 0;
}
}
return result;
}
function readReverseBase64(){
if (!base64Str) return END_OF_INPUT;
while (true){
if (base64Count >= base64Str.length) return END_OF_INPUT;
var nextCharacter = base64Str.charAt(base64Count);
base64Count++;
if (reverseBase64Chars[nextCharacter]){
return reverseBase64Chars[nextCharacter];
}
if (nextCharacter == 'A') return 0;
}
return END_OF_INPUT;
}
function ntos(n){
n=n.toString(16);
if (n.length == 1) n="0"+n;
n="%"+n;
return unescape(n);
}
function decodeBase64(str){
setBase64Str(str);
var result = "";
var inBuffer = new Array(4);
var done = false;
while (!done && (inBuffer[0] = readReverseBase64()) != END_OF_INPUT
&& (inBuffer[1] = readReverseBase64()) != END_OF_INPUT){
inBuffer[2] = readReverseBase64();
inBuffer[3] = readReverseBase64();
result += ntos((((inBuffer[0] << 2) & 0xff)| inBuffer[1] >> 4));
if (inBuffer[2] != END_OF_INPUT){
result += ntos((((inBuffer[1] << 4) & 0xff)| inBuffer[2] >> 2));
if (inBuffer[3] != END_OF_INPUT){
result += ntos((((inBuffer[2] << 6) & 0xff) | inBuffer[3]));
} else {
done = true;
}
} else {
done = true;
}
}
return result;
}
var digitArray = new Array('0','1','2','3','4','5','6','7','8','9','a','b','c','d','e','f');
function toHex(n){
var result = ''
var start = true;
for (var i=32; i>0;){
i-=4;
var digit = (n>>i) & 0xf;
if (!start || digit != 0){
start = false;
result += digitArray[digit];
}
}
return (result==''?'0':result);
}
function pad(str, len, pad){
var result = str;
for (var i=str.length; i<len; i++){
result = pad + result;
}
return result;
}
function encodeHex(str){
var result = "";
for (var i=0; i<str.length; i++){
result += pad(toHex(str.charCodeAt(i)&0xff),2,'0');
}
return result;
}
function decodeHex(str){
str = str.replace(new RegExp("s/[^0-9a-zA-Z]//g"));
var result = "";
var nextchar = "";
for (var i=0; i<str.length; i++){
nextchar += str.charAt(i);
if (nextchar.length == 2){
result += ntos(eval('0x'+nextchar));
nextchar = "";
}
}
return result;
}
//--></script>
</head>
<body>
<form name=code onsubmit="return false()">
<textarea name=text style='width:100%;height:75%;' onfocus='if (this.value=="Enter text to encode or decode here."){this.value="";}'>Enter text to encode or decode here.</textarea>
<table>
<tr><td align=center>
<input value="Encode" type=button onclick="document.code.text.value=urlEncode(document.code.text.value);">
</td><td align=center>
URL
</td><td align=center>
<input value="Decode" type=button onclick="document.code.text.value=urlDecode(document.code.text.value);">
</td></tr>
<tr><td align=center>
<input value="Encode" type=button onclick="document.code.text.value=encodeBase64(document.code.text.value);">
</td><td align=center>
Base 64
</td><td align=center>
<input value="Decode" type=button onclick="document.code.text.value=decodeBase64(document.code.text.value);">
</td></tr>
<tr><td align=center>
<input value="Encode" type=button onclick="document.code.text.value=encodeHex(document.code.text.value);">
</td><td align=center>
Hex
</td><td align=center>
<input value="Decode" type=button onclick="document.code.text.value=decodeHex(document.code.text.value);">
</td></tr>
<tr><td align=center>
</td><td align=center>
<input type=reset value=Clear>
</td><td align=center>
</td></tr>
</table>
</form>
<hr>
Base64 encode/decode was ported from a <a href="http://ostermiller.org/utils/Base64.html">Java Base64 encoder/decoder</a>.<br>
Base64 encode/decode was ported to <a href="http://ostermiller.org/base64_actionscript.html">Macromedia Actionscript</a>.<br>
<h3>License</h3>
<p>This program is free software; you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by the Free
Software Foundation; either version 2 of the License, or (at your option)
any later version.</p>
<p>This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the
<a href="http://www.gnu.org/copyleft/gpl.html">GNU
General Public License</a> for more details.</p>
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<div style="padding:0.2cm;"><p>Copyright <a href="http://ostermiller.org/contact.pl?regarding=JavaScript+Encoding" class=mail>Stephen Ostermiller</a> 2003-2006</p></div>
</body>
</html>