4 ms·
The world changes once you realize why usually encryption is capped at AES256...
by swijck 2y ago
The world changes once you realize why usually encryption is capped at AES256...
- oconnore 2y ago256 bit symmetric cryptography keys are a bit like picking one atom in the universe (10^80 atoms, or 100000000000000000000000000000000000000000000000000000000000000000000000000000000). Your opponent would have to test half of the atoms in the universe to have a reasonable chance of getting the right key. That's generally understood to be not feasible.
- alwayslikethis 2y agohttps://www.schneier.com/blog/archives/2009/09/the_doghouse_cr.html https://www.schneier.com/blog/archives/2009/09/the_doghouse_... It's more than that. Simply incrementing your way through a 256 bit counter is impossible by the thermodynamic cost alone.
- swijck 2y agoCorrect. Better to get into other forms of cryptography than pointlessly increase the numbers. We need to think more about PQ proofing.
- tatersolid 2y agoAES-256 is already post-quantum secure; what exactly are you suggesting?
- brokenmachine 2y agoHe could get lucky though. :-P
- ziddoap 2y agoCare to enlighten us? What did you realize?
- levkk 2y agoIt's too CPU heavy and your webservers crash under load would be my guess, for no added benefit [1] of course. [1] https://security.stackexchange.com/questions/14068/why-most-people-use-256-bit-encryption-instead-of-128-bit https://security.stackexchange.com/questions/14068/why-most-...
- swijck 2y agoCorrect. Anything higher is an order of magnitude more computationally expensive to do for no real reasonable gain. Multiple layers of encryption get you there far enough. Better to dig deeper into other cryptography methods than try increase AES beyond 256. Its already rather insane how quickly decryption happens.
- coppsilgold 2y agoYou can trivially modify the AES key schedule to have a key size of any length (ex. replace it with a hash function or a sponge construct) and have any number of increased rounds in the AES permutation. Performance impact will linearly scale with the number of rounds. You can even have no key schedule at all and just make your AES key size in bits = 128 * num_of_rounds. This doesn't mean that the bruteforce complexity is going to be that high but that would hardly matter...
- ziddoap 2y agoHmm, not sure how this was supposed to change my world. I thought you had some secret cabal conspiracy or something to share.
- swijck 2y agoSorry... I'm boring and easily excited :p