Doc #62453 [Opn]: Terrible sample code for mcrypt_encrypt

Edit report at https://bugs.php.net/bug.php?id=62453&edit=1 ID: 62453 Updated by: nikic@php.net Reported by: maarten dot bodewes at gmail dot com -Summary: Terrible sample code +Summary: Terrible sample code for mcrypt_encrypt Status: Open Type: Documentation Problem Package: Documentation problem PHP Version: 5.4.4 -Assigned To: +Assigned To: ircmaxell Block user comment: N Private report: N New Comment: Assigning to ircmaxell in hope that he can review this and apply the changes :) Previous Comments: ------------------------------------------------------------------------ [2012-06-30 14:08:11] maarten dot bodewes at gmail dot com Created patch on the original sample code (including PHP header/footer) using the following requirements. Tested against Java code (send to Nikic). Requirements: * use MCRYPT_RIJNDAEL_128 (AES) instead of MCRYPT_RIJNDAEL_256 * use CBC mode encryption * use a 128 bit (16 byte), 192 (24 bit) or 256 bit (32 byte) key specified in hexadecimals consisting of random bytes * use a random IV (already present), and prepend that to the cipher text (so it can be used during decryption) * perform an explicit encoding (UTF-8 would come to mind) on the plain text, or specify that UTF-8 encoding is being used for compatability reasons * base64 encode the resulting cipher text, as most of web programmers use strings Furthermore the following warnings should be present: * PKCS#7 padding should be used on binary plain "text" * this CBC encryption mode only provided confidentiality, not integrity or authentication * padding oracle attacks may reveal the plain text in client/server setups ------------------------------------------------------------------------ [2012-06-30 11:14:01] nikic@php.net Could you maybe provide a better example for the function? I don't know anything about the topic at hand, so I probably can't come up with a good example on my own. ------------------------------------------------------------------------ [2012-06-29 23:49:49] maarten dot bodewes at gmail dot com Description: ------------ --- From manual page: http://www.php.net/function.mcrypt-encrypt#refsect1-function.mcrypt-encrypt-examples --- Hi, I'm a security professional (+10 years experience). I'm wondering which arse wrote that PHP sample this bug is pointing at. The following mistakes are present (at the minimum): * using an IV with ECB encoding * using ECB at all for non random plain text * using ECB within an example in the first place * mistaking a passphrase with a key (keys should be random bytes of data, or at least generated using e.g. PBKDF2, bcrypt or scrypt) * supplying an incorrect number of characters for the key (25 if I'm not mistaken) * using MCRYPT_RIJNDAEL_256 instead of MCRYPT_RIJNDAEL_128 (AES) * not performing PKCS#7 padding by default If this sample is to coax unsuspecting people in writing insecure code which is not compatible with any crypto library out there, keep it in. Otherwise toss it out and start over again. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=62453&edit=1