On Tue, Dec 11, 2001 at 01:00:40AM +0100, Dries Kimpe wrote: > > Hi, > > this is something I've been wondering for some time now: > Is it possible (or at least much easier) to extract the encryption key > if you both have the encrypted and original data? > > Dries > > PS. I know it isn't debian-related, but it's a good question anyway...
It's called a known-plaintext attack. The answer depends on the encryption scheme, but one of the properties of a good scheme is that having a plaintext won't help you recover the key. In fact, this is an essential requirement for public-key cryptography, because the enemy can generate as much encrypted+plaintext data as they like. ...unless you are from Hollywood - in which case a good encryption scheme is one that can be cracked by having lots of digits flash up on the screen, and gradually have individual digits lock into the correct key. Andrew -- Andrew Bolt, [EMAIL PROTECTED] 110 Fulbourn Road, Cambridge, CB1 9NJ, ENGLAND, +44 1223 400650 -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]