Bug #72362 [Opn->Asn]: OpenSSL Blowfish encryption is incorrect for short keys

Edit report at https://bugs.php.net/bug.php?id=72362&edit=1 ID: 72362 Updated by: bukka@php.net Reported by: sachavav at tut dot by Summary: OpenSSL Blowfish encryption is incorrect for short keys -Status: Open +Status: Assigned Type: Bug Package: OpenSSL related Operating System: Linux/Ubuntu PHP Version: 5.6.22 -Assigned To: +Assigned To: bukka Block user comment: N Private report: N New Comment: So this is happening for exactly the same reason as https://bugs.php.net/bug.php?id=71917 (we don't try to set key length for variable length ciphers if the key is shorter than the default key size for the algorithm). Unfortunately changing that as default would have exactly the same implication in terms of BC. It would stop working for people using shorter keys and relying on the fact that is filled with \0. So I would be inclined to introduce a new option for that which could possibly go to 7.1 if RM is fine with that or master (7.2) otherwise. I will create a PR. Previous Comments: ------------------------------------------------------------------------ [2016-06-08 12:35:29] sachavav at tut dot by Description: ------------ According to description of Blowfish algorithm it can use variable key starting from 32bits. If the key is shorter than block, it should be cycled over. https://www.schneier.com/academic/archives/1994/09/description_of_a_new.html Keys A - AA - AAA should be equivalent. This is true in openssl extension for keys, longer than 128 bits, but for shorter keys extension works incorrectly. It padds short keys with zeros up to 128 bits instead of cycling them. Please check sample code for explanation. If you can compare behavior of mcrypt extension - it works correctly there. Test script: --------------- > php -r 'echo bin2hex(openssl_encrypt("this is a test > string","bf-ecb","12345678" , OPENSSL_RAW_DATA));' 0b30345b335e2ca5ba4d12c0077768c99680ca260b07d693 > php -r 'echo bin2hex(openssl_encrypt("this is a test > string","bf-ecb","12345678\0\0\0\0\0\0\0\0" , OPENSSL_RAW_DATA));' 0b30345b335e2ca5ba4d12c0077768c99680ca260b07d693 > php -r 'echo bin2hex(openssl_encrypt("this is a test > string","bf-ecb","1234567812345678" , OPENSSL_RAW_DATA));' e3214d1b16e574828c8a3e222202dde81afd1ad2cb165ab3 Expected result: ---------------- Short keys are cycled over. Actual result: -------------- Short keys are padded with zeros ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=72362&edit=1