On 10/07/17 20:07, Blumenthal, Uri - 0553 - MITLL wrote: > My $0.02: absolutely not on the Standards Track (for reasons already > expressed by others), might be discussable if Informational.
I haven't checked, but as far as I recall, other wiretapping RFCs inconsistent with 2804 have all been in the ISE stream (or predate it) and have all documented already deployed wiretapping schemes. I think that is consistent with 2804 and using a WG list and WG participant cycles/attention to debate/develop wiretapping methods does go against 2804 and ought not be done. S. > > -- Regards, Uri Blumenthal > > On 7/10/17, 15:03, "TLS on behalf of Nico Williams" > <tls-boun...@ietf.org on behalf of n...@cryptonector.com> wrote: > > On Mon, Jul 10, 2017 at 08:01:32PM +0300, Yoav Nir wrote: >>> On 10 Jul 2017, at 17:16, Stephen Farrell >>> <stephen.farr...@cs.tcd.ie> wrote: >>>> 2. this proposal offers significantly better security >>>> properties than current practice (central distribution of >>>> static RSA keys) >>> >>> I fail to see any relevant difference in security properties >>> between those two, never mind a significant improvement. >> >> I can see one way in which it is worse. >> >> With static RSA keys, you can configure the server to use only PFS >> ciphesuites (ECDHE-RSA or DHE-RSA). If you want to enable the >> non-FS, you need to switch to RSA ciphersuites, and that would be >> obvious to any client. In fact, I think today a server would stick >> out if it only supported RSA ciphersuites. >> >> There is no way to know that a server is doing what it says in the >> draft. It’s completely opaque to the client. >> >> However, in both cases the server does get FS. As long as the >> server has not enabled RSA ciphersuites or exportable private key >> shares, any recorded TLS stream is safe even if the attacker later >> gets the private key. > > Well, a client could observe reuse of server ECDHE public keys... > > And servers can always share session keys with an auditing system. > There's no way a client could detect this. > > I don't think we need to have the client KNOW what the server is > doing because... how the heck can the server prove it's not > publishing the client's secrets?? The server simply cannot prove > that it is adhering to any privacy policy. > > Brief reuse of server ECDHE public keys is an optimization. I > _think_ it's a safe optimization, and it's safer the shorter the > reuse period is -- and correspondingly less safe the longer the reuse > period. > > But I would prefer that anyone wanting auditability just build that > into their implementations as a proper audit capability. Yes, it's > more complex to later decrypt sessions, but it also doesn't mess with > the protocol in any way. > > That said, I wouldn't object to the proposal if it meant to be > Informational. I don't see how a document that describes a possible > a configuration (not protocol!) that is not relevant to the Internet > should be a Standards-Track RFC, or BCP for that matter. > Informational will do. > > Nico -- > > _______________________________________________ TLS mailing list > TLS@ietf.org https://www.ietf.org/mailman/listinfo/tls > > > > > _______________________________________________ TLS mailing list > TLS@ietf.org https://www.ietf.org/mailman/listinfo/tls >
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