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run code in 300+ PHP versions simultaneously
<?php function decrypt($a) { $a1 = strtolower(strrev($a)); $a2 = hexdec(substr($a1,0,4)) ^ hexdec('BFF') ^ hexdec('D77D'); $a3 = substr($a1,4); $a5 = 0; unset($ans); for($a5=0;$a5<strlen($a3);$a5+=6){ ++$a6; $mul=$a6 * $a6; $a7=$mul ^ hexdec('6E'); $ans = $ans . chr(octdec(hexdec(substr($a3,$a5,6))) ^ hexdec('AFE43') ^ hexdec('399AA3') ^ $a7 ^ $a2); } return $ans; } echo decrypt('299BFD579BFD8B9BFDE9ABFD2EABFD84ABFD28ABFD07BBFDB9BBFDE1BBFD74BBFD97CBFDA4CBFD45CBFD36CBFDB0CBFD8EBBFD00CBFD0FBBFD41CBFDCFBBFDAFBBFD5DDD'); define('__FLAG__', 'flag{hidden_flag}'); if(decrypt("DEFBFD2EFBFDBCFBFD58FBFD56FBFD31FBFDDFEBFD3BEBFD48EBFD16EBFD83EBFD2DDBFDDFDBFDBCDBFDCBDBFD87DBFDB9DBFDB5DBFD76DBFDF6DBFDF5DBFDD5DBFD82ED") == 'pwning_the_phpreverse!') { echo __FLAG__; } ?>

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43.39 ms | 402 KiB | 5 Q