Hi, Seokung. For section 2.2, I *still* think it would be good to be totally explicit as I said: Something like: - At the sender: perform step 7 before step 5. - At the receiver: perform the second half of step 5 (perform verification) after step 6. This means that authentication is performed on the cleartext rather than the ciphertext.
Presumably this applies equally to SRTCP? You should say so if it is true. It occurs to me (belatedly) that this reordering apparently increases the processing that has to be done on packets before the authentication is verified, providing a greater impact for a DoS attack that modifies the encrypted payload. I think this should be noted in the security considerations (assuming I am correct). Is this a significant problem given encryption is mandatory on some packets? The other problem was fixed. Regards, Elwyn David McGrew wrote: > Hi Seokung > > It looks like almost all of my comments were addressed. I did notice a > couple things, though. The first is important, the second is very minor. > >> >> There is no definition of how CCM and GCM are to be used to protect >> RTCP. It would not be possible to use this specification to protect >> RTCP packets with those algorithms. > > The new draft says "In case of SRTCP, the Authentication Portion > described in Fig.2 of [RFC3711] is treated as AAD." Is that true even > if the E bit is equal zero? I suspect that what you want here is to > have a definition such that, when E=0, the AAD format for SRTCP is > specified differently. (Either that or a restriction to not use E=0.) > >> >> >> In Section 2, I don't understand the meaning of "and valuables" and I >> suggest just removing the phrase. >> > > I notice that the word is still there. Perhaps "variables" was the > intended word? > > Apologies for the lag in my getting this review done. > > Best regards, > > David > > > On Apr 2, 2009, at 6:14 AM, 윤석웅 wrote: > >> Dear David Mcgrew and Elwyn Davies. >> >> >> Thanks for your lots of comments during AD last call. >> >> I really appreciated it. >> >> >> Here is the revised draft to reflect whole your comments. >> >> Please check if thers is any problem or deficiency. >> >> >> If you are OK, I will submit it to proceed next step. >> >> >> BR, >> >> Seokung >> >> <draft-ietf-avt-seed-srtp-10(alpha).txt> > _______________________________________________ Gen-art mailing list [email protected] https://www.ietf.org/mailman/listinfo/gen-art
