If the Block Cipher goes away, this will simply be the "encrypted" method. No need to bikeshed the name for now.
On Wed, Oct 6, 2021 at 4:21 PM Phillip Hallam-Baker <[email protected]> wrote: > I think this is a different cryptographic construct and we should create a > name for the generic. Something like Keyed Permutation. > > Rather than bikeshed the name here, I propose taking it to either CFRG or > the Cryptography list (or both) to socialize the concept. It is quite > possible that there is a prior nomenclature we should follow. > > > It is not clear to me what the precise security properties required here > are. For my particular application, they are fairly weak because I am only > providing some traffic analysis resistance. I am not interested in > plaintext recovery attack, but I do care about the attacker being able to > discover that E(n), E(N+1) are a sequence. > > None of my systems are going to collapse if this primitive is broken but > it might afford a foothold. > > > On Wed, Oct 6, 2021 at 6:13 PM Martin Thomson <[email protected]> wrote: > >> On Thu, Oct 7, 2021, at 07:02, Christian Huitema wrote: >> > Phil, >> > >> > What we have in the current LB spec is called a "stream cipher", but >> > that's a misnomer. What we have in the spec is actually a variable size >> > block cipher, derived from AES-ECB using a construct similar to FFX. >> > Your review of that algorithm would be appreciated. >> >> Christian, >> >> I would call this a Feistel network, but avoid talking about FFX. FFX >> has a bunch of guidance about the number of iterations of the network that >> this ignores; to call this FFX or even imply that it is FFX isn't really >> fair. When you get right down to it, the real contribution in FFX is the >> analysis that produces guidance on the number of iterations and the >> inclusion of tweaks; if you use neither, then it's not really FFX. As >> additional iterations are necessary to maintain a security level, we need >> to be careful about the claims we make in relation to security. >> >>
