note 117499 added to function.openssl-encrypt

Beware of the padding this method adds ! <?php $encryption_key = openssl_random_pseudo_bytes(32); $iv = openssl_random_pseudo_bytes(16); $data = openssl_random_pseudo_bytes(32); for ($i = 0; $i < 5; $i++) { $data = openssl_encrypt($data, 'aes-256-cbc', $encryption_key, OPENSSL_RAW_DATA, $iv); echo strlen($data) . "\n"; } ?> With this sample the output will be: 48 64 80 96 112 This is because our $data is already taking all the block size, so the method is adding a new block which will contain only padded bytes. The only solution that come to my mind to avoid this situation is to add the option OPENSSL_ZERO_PADDING along with the first one: <?php $data = openssl_encrypt($data, 'aes-256-cbc', $encryption_key, OPENSSL_RAW_DATA|OPENSSL_ZERO_PADDING, $iv); ?> /!\ Be careful when using this option, be sure that you provide data that have already been padded or that takes already all the block size. ---- Server IP: 72.52.91.14 Probable Submitter: 109.24.149.197 ---- Manual Page -- http://php.net/manual/en/function.openssl-encrypt.php Edit -- https://master.php.net/note/edit/117499 Del: integrated -- https://master.php.net/note/delete/117499/integrated Del: useless -- https://master.php.net/note/delete/117499/useless Del: bad code -- https://master.php.net/note/delete/117499/bad+code Del: spam -- https://master.php.net/note/delete/117499/spam Del: non-english -- https://master.php.net/note/delete/117499/non-english Del: in docs -- https://master.php.net/note/delete/117499/in+docs Del: other reasons-- https://master.php.net/note/delete/117499 Reject -- https://master.php.net/note/reject/117499 Search -- https://master.php.net/manage/user-notes.php