Thanks Eric, Let's see what folks say in response to this and I can post anything not immediately resolved as a DISCUSS ballot. We can then process that in the coming week or two, and you can take over the DISCUSS for whatever's not resolved by the swap-over in Chicago. Or if someone else wants to make some or all of Eric's comments a DISCUSS that'd work too, but I'm fine with taking it.
Cheers, S. On 15/03/17 14:44, Eric Rescorla wrote: > Sorry for the late review of this document. I just got to it this > week. I'm sending this as comments rather than issues/PR due to > how late it is in the proces. > > I have two high-level comments: > > - This document seems to still have a bunch of material about > static DH (especially static DH authentication). I thought we > had agreed to remove that. > > - You are inconsistent about using capital 2119 language > and I expect you want to be consistent. > > > DETAILED > S 2. > All of these key exchange algorithms provide forward secrecy. > > This is actually only true if each side generates fresh ephemerals > which does not seem to be required by the spec. > > Do we really want to promote ECDH_anon to standards track? > > > Nit: you want a line break between the last line of Figure 1 > and the legend explaining the message types. > > > S 2.3. > This specification does not impose restrictions on signature schemes > used anywhere in the certificate chain. The previous version of this > document required the signatures to match, but this restriction, > originating in previous TLS versions is lifted here as it had been in > RFC 5246. > > This section is about ECDH_anon, so maybe this text belongs in S 2.1 or > 2.2.? > > > S 3. > You have a bunch of lower case 2119 key words here. > > If these conditions are not met, the client should send a client > Certificate message containing no certificates. In this case, the > ClientKeyExchange should be sent as described in Section 2, and the > CertificateVerify should not be sent. If the server requires client > authentication, it may respond with a fatal handshake failure alert. > > Actually, this "should not be sent" is a MUST NOT, because if you send > an empty certificate, you're forbidden to send CertificateVerify. > > > S 4. > choice of curves and compression techniques specified by the client. > > s/compression techniques/point formats/? > > > S 5.1.1. > Do you want to rename elliptic_curve_list to named_curve_list? > > > S 5.1.2. > > Three point formats were included in the definition of ECPointFormat > above. This specification deprecates all but the uncompressed point > format. Implementations of this document MUST support the > uncompressed format for all of their supported curves, and MUST NOT > support other formats for curves defined in this specification. For > backwards compatibility purposes, the point format list extension > MUST still be included, and contain exactly one value: the > uncompressed point format (0). > > This implies that you have to send supported point formats, but in > S 5.1, this is a SHOULD. I believe what you may be trying to say > here is that if you send the extension, it must be non-empty. > > Also, maybe I'm missing it, but where do you say that the default > is to assume that the other side supports uncompressed if it doesn't > do so. This is a backwards compat issue. > > > S 5.3. > You don't define what "authorized for signatures" is, but I suspect > you're talking about KeyUsage, etc.? If so, don't you need to say > this about ECDHE_ECDSA as well. > > S 5.4. > The value named_curve indicates that a named curve is used. This > option SHOULD be used when applicable. > > When would you not? > > S 5.5. > This defines: > rsa_fixed_ecdh(65), > ecdsa_fixed_ecdh(66), > > But the specification doesn't actually support this. Note that > the fixed_DH authentication mechanism are specified as having > the client's cert be on the same curve as the long-term > ECDH key, but you've deprecated those KE mechanisms, so as far > as I can tell, static DH auth is impossible > > Also: > 1. Why isn't the ECDSA cert required to be signing capable. > 2. You probably should standardize on ECDSA_sign or ecdsa_sign. > > S 5.7. > More text about static DH auth. Also "implicit" can probably go away. > > The client selects an ephemeral ECDH public key corresponding to the > parameters it received from the server according to the ECKAS-DH1 > scheme from IEEE 1363. It conveys this information to the client in > the ClientKeyExchange message using the format defined above. > > I don't understand what this means. > > > S 5.8. > This message is sent when the client sends a client certificate > containing a public key usable for digital signatures, e.g., when the > client is authenticated using the ECDSA_sign mechanism. > > This is the only way that things can work now. > > > S 5.1.1. > Failing to > do so allows attackers to gain information about the private key, to > the point that they may recover the entire private key in a few > requests, if that key is not really ephemeral. > > To the best of my knowledge, this only applies to DH, not signature > verification. > > S 6. > Do we really want to promote NULL and 3DES to ST? > > -Ekr > > > > _______________________________________________ > TLS mailing list > TLS@ietf.org > https://www.ietf.org/mailman/listinfo/tls >
signature.asc
Description: OpenPGP digital signature
_______________________________________________ TLS mailing list TLS@ietf.org https://www.ietf.org/mailman/listinfo/tls
