PHP 简单对称加密算法之加密|解密

/**
 * 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 = '', $skey = 'cxphp') {
    $strArr = str_split(base64_encode($string));
    $strCount = count($strArr);
    foreach (str_split($skey) as $key => $value)
        $key < $strCount && $strArr [$key] .= $value;
    return str_replace(array(
        '=',
        '+',
        '/'
            ), array(
        'O0O0O',
        'o000o',
        'oo00o'
            ), join('', $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 = '', $skey = 'cxphp') {
    $strArr = str_split(str_replace(array(
        'O0O0O',
        'o000o',
        'oo00o'
                    ), array(
        '=',
        '+',
        '/'
                    ), $string), 2);
    $strCount = count($strArr);
    foreach (str_split($skey) as $key => $value)
        $key <= $strCount && $strArr [$key] [1] === $value && $strArr [$key] = $strArr [$key] [0];
    return base64_decode(join('', $strArr));
}