RE: Extensibility

[Dan Simon <dansimon@xxxxxxxxxxxxx>]

>
>From: 	Tom Weinstein[SMTP:tomw@xxxxxxxxxxxx]
>
>> No one is suggesting that complex extra features be added willy-nilly
>> without careful consideration of their security implications. 
>> However, to neglect to account for possible (and possibly necessary)
>> improvements in the protocol beyond those that can be addressed by
>> versioning (particularly possible changes to the first handshake
>> message sent) would be, in my opinion, sheer reckless hubris.  SSL 3.0
>> currently lacks, and TLS desperately needs, a mechanism for
>> incorporating such improvements.
>
>This is completely untrue.  Although SSL 3.0 does not have a formal
>mechanism for extension, such as the X protocol has, it does provide for
>compatibility with future versions.

Well, it has been pointed out to me that the latest SSL 3.0 errata sheet
includes the addition of just such a mechanism--to wit:

Section 7.6.1.2

For forward compatibility reasons, it's legal for a client hello message
to have extra data after the compression methods. This data should be
included in the handshake hashes, but otherwise ignored.

This looks to me like exactly what I was looking for.  Let's just hope
that the TLS editors are more up-to-date than I am.
 
>Why are
>you flogging this dead horse?

When last I checked, it was still alive, but apparently someone killed
it while I wasn't looking.  Apologies to all.


				Daniel Simon
				Cryptographer, Microsoft Corp.
				(dansimon@xxxxxxxxxxxxx)
>
>