A reversible encryption function authcode function code in UCenter_PHP tutorial

Copy code The code is as follows:

function authcode($string, $operation = 'DECODE', $key = '', $expiry = 0) {

$ckey_length = 4; // The random key length ranges from 0-32;
// Adding a random key can make the ciphertext irregular, even if the original text and cipher text are If the key is exactly the same, the encryption result will be different every time, which increases the difficulty of cracking.
// The larger the value, the greater the ciphertext change pattern. Ciphertext change = 16 to the power of $ckey_length
// When this value is 0, no random key will be generated

$key = md5($key ? $key : UC_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)) ;
}
}
/***************************************************************************/
$string = authcode("Hello","ENCODE","HTML_TCCJ_AUTH");
echo $string,'< ;br/>';
echo authcode($string,"DECODE","HTML_TCCJ_AUTH"),'
';

http://www.bkjia.com/PHPjc/322235.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/322235.htmlTechArticleCopy the code as follows: function authcode($string, $operation = 'DECODE', $key = '', $expiry = 0) { $ckey_length = 4; // The random key length ranges from 0-32; // Adding a random key can...