On 5 November 2018 at 10:18, Gilad Ben-Yossef <gilad@xxxxxxxxxxxxx> wrote: > Hi Stephan, > > On Mon, Nov 5, 2018 at 10:50 AM Stephan Mueller <smueller@xxxxxxxxxx> wrote: >> >> Am Sonntag, 4. November 2018, 11:05:24 CET schrieb Gilad Ben-Yossef: >> >> Hi Gilad, >> >> > As per Sp800-38A addendum from Oct 2010[1], cts(cbc(aes)) is >> > allowed as a FIPS mode algorithm. Mark it as such. >> > >> > [1] https://csrc.nist.gov/publications/detail/sp/800-38a/addendum/final >> >> There are several types of CTS approaches. Only three of those are listed in >> the SP800-38A addendum. The source code only refers to some RFCs. >> >> Did you check whether the CTS implementation matches one or more of the types >> listed in the addendum? If yes, may I suggest to add a small statement in the >> code noting this fact? > > Yes, AFAIK the software implements CBC-CS3 as described in the document. > You have a very good point about this not document anywhere. I will > send a patch. > I agree that it makes sense to document this. > While we're at it, does someone find it useful if I implemented the > other two modes? > They are part of the standard as well, although I am not sure that in > itself is sufficient cause. > Nope. The linux crypto API is not a general purpose cryptography toolkit, it should only offer what we actually use in the kernel, or we'll either end up with bitrot or with a disproportionate maintenance burden for stuff nobody actually uses.
