PHP encryption and Decryption Method 2

<?php/* * @param $string the string to encrypt or resolve * @param $operation Encrypt/decrypt encode encryption, DECODE decrypt * @param $key encryption/Resolution factor */function AUTHC    Ode ($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, (+). $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 <, $i + +) {$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, ten) = = 0 | | substr ($result, 0,)-time () > 0) &&    SUBSTR ($result, ten, +) = = substr (MD5 ($result, $keyb), 0, (+)) {return substr ($result, 26);    } else {return ';    }} else {return $KEYC. Str_replace (' = ', ' ', Base64_encode ($result)); }//encryption $ok $str = ' 123456 '; $ok = Authcode ($str, ' ENCODE '); Echo $ok, "<br/>";//Decrypt $ok 1$ok1 = Authcode ($ok, ' DE CODE '); echo $ok 1;? >

　　

PHP encryption and Decryption Method 2