3 ms·
I fully agree on the cypher then MAC policy. Deciphering is time consuming and by feeding bogus data could be used in a DOS attack. Without prior checking it ma
by chmike 17y ago
I fully agree on the cypher then MAC policy. Deciphering is time consuming and by feeding bogus data could be used in a DOS attack. Without prior checking it may be possible to indirectly probe the deciphering process.
What I am not so sure is the choice of CTR. I currently prefer CFB.
- tptacek 17y ago... because?
- chmike 17y agoCTR cyphers a value that changes with only a few bits, while CFB uses previous output which is much more random, though exposed, since it is the ciphered text. PS: http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation http://en.wikipedia.org/wiki/Block_cipher_modes_of_operation makes it clear.
- tptacek 17y agoSecurity under those circumstances is a design requirement for AES. CTR is secure if AES is secure. If known plaintext pairs differing in only a few bits break AES, we have bigger problems than CTR mode.