# Determine AES key given encrypted and unencrypted files

Given an encrypted file, the original unencrypted (cleartext) file, and knowledge of which AES encryption algorithm was used, is it possible to determine the key that was used to encrypt the data in a reasonable period of time?

I am not looking for details on how AES works, just a simple answer.

• – Ilmari Karonen Dec 7 '18 at 1:10
• This is a 2-year old question with an accepted answer. I've moved long past this and have no idea why it's being revived, but thank you @IlmariKaronen – andrewgu Dec 7 '18 at 22:28
• There was a (rather poor) new answer that bumped it to the front page. That answer has since been deleted. But since I noticed that your question is rather similar to a bunch of others here, I figured linking them would be useful. Arguably, some of those questions might even qualify as duplicates, but since they all have decent answers already, closing or merging them would be a lot of work for little if any gain. – Ilmari Karonen Dec 7 '18 at 22:38

• As far as is publicly known. $\;$ – user991 Jul 18 '15 at 1:01