php 加密解密方法2

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<?php/* * @param $string 要加密或解決的字串 * @param $operation 加密/解密 ENCODE加密, DECODE 解密 * @param $key 加密/解決因子*/function authcode($string, $operation = ‘DECODE‘, $key = ‘12345678‘, $expiry = 0) {    $ckey_length = 4;    $key  = md5($key);    $keya = md5(substr($key, 0, 16));    $keyb = md5(substr($key, 16, 16));    $keyc = $ckey_length ? ($operation == ‘DECODE‘ ? substr($string, 0, $ckey_length): substr(md5(microtime()), -$ckey_length)) : ‘‘;    $cryptkey = $keya.md5($keya.$keyc);    $key_length = strlen($cryptkey);    $string = $operation == ‘DECODE‘ ? base64_decode(substr($string, $ckey_length)) : sprintf(‘%010d‘, $expiry ? $expiry + time() : 0).substr(md5($string.$keyb), 0, 16).$string;    $string_length = strlen($string);    $result = ‘‘;    $box = range(0, 255);    $rndkey = array();    for($i = 0; $i <= 255; $i++) {    $rndkey[$i] = ord($cryptkey[$i % $key_length]);    }    for($j = $i = 0; $i < 256; $i++) {    $j = ($j + $box[$i] + $rndkey[$i]) % 256;    $tmp = $box[$i];    $box[$i] = $box[$j];    $box[$j] = $tmp;    }    for($a = $j = $i = 0; $i < $string_length; $i++) {    $a = ($a + 1) % 256;    $j = ($j + $box[$a]) % 256;    $tmp = $box[$a];    $box[$a] = $box[$j];    $box[$j] = $tmp;    $result .= chr(ord($string[$i]) ^ ($box[($box[$a] + $box[$j]) % 256]));    }    if($operation == ‘DECODE‘) {    if((substr($result, 0, 10) == 0 || substr($result, 0, 10) - time() > 0) && substr($result, 10, 16) == substr(md5(substr($result, 26).$keyb), 0, 16)) {    return substr($result, 26);    } else {    return ‘‘;    }    } else {    return $keyc.str_replace(‘=‘, ‘‘, base64_encode($result));    }    }// 加密 $ok$str = ‘123456‘;$ok = authcode($str, ‘ENCODE‘);echo $ok , "<br />";// 解密 $ok1$ok1 = authcode($ok, ‘DECODE‘);echo $ok1;?>

　　

php 加密解密方法2