简单PHP对称加密解密方法

/**
 * 简单对称加密算法之加密
 * @param String $string 需要加密的字串
 * @param String $skey 加密EKY
 * @author Anyon Zou <zoujingli@qq.com>
 * @date 2013-08-13 19:30
 * @update 2014-10-10 10:10
 * @return String
 */
function encode($string = &#39;&#39;, $skey = &#39;cxphp&#39;) {
    $strArr = str_split(base64_encode($string));
    $strCount = count($strArr);
    foreach (str_split($skey) as $key => $value)
        $key < $strCount && $strArr[$key].=$value;
    return str_replace(array(&#39;=&#39;, &#39;+&#39;, &#39;/&#39;), array(&#39;O0O0O&#39;, &#39;o000o&#39;, &#39;oo00o&#39;), join(&#39;&#39;, $strArr));
}
/**
 * 简单对称加密算法之解密
 * @param String $string 需要解密的字串
 * @param String $skey 解密KEY
 * @author Anyon Zou <zoujingli@qq.com>
 * @date 2013-08-13 19:30
 * @update 2014-10-10 10:10
 * @return String
 */
function decode($string = &#39;&#39;, $skey = &#39;cxphp&#39;) {
    $strArr = str_split(str_replace(array(&#39;O0O0O&#39;, &#39;o000o&#39;, &#39;oo00o&#39;), array(&#39;=&#39;, &#39;+&#39;, &#39;/&#39;), $string), 2);
    $strCount = count($strArr);
    foreach (str_split($skey) as $key => $value)
        $key <= $strCount  && isset($strArr[$key]) && $strArr[$key][1] === $value && $strArr[$key] = $strArr[$key][0];
    return base64_decode(join(&#39;&#39;, $strArr));
}
echo &#39;<pre class="brush:php;toolbar:false">&#39;;
$str = &#39;56,15123365247,54,四大古典风格&#39;;
echo "string : " . $str . " <br />";
echo "encode : " . ($enstring = encode($str)) . &#39;<br />&#39;;
echo "decode : " . decode($enstring);
die();