Re: [TLS] Security concerns around co-locating TLS and non-secure on same port (WGLC: draft-ietf-tsvwg-iana-ports-08)

[Marsh Ray <[e-mail]>]

On 11/08/2010 02:12 PM, Nicolas Williams wrote:
> On Mon, Nov 08, 2010 at 05:07:42PM +0800, Paul Hoffman wrote:
>
>> "be complexer to implement than using two ports": See the state
>> machine described in section 4 and its subsections in RFC 3207. That's
>> much more complex than "OK, let's go".
>
> This is true.  Specifically it complicates the task of making the
> security layer transparent to the application.  But really, not _that_
> much.

Does it have implications for session resumption I wonder?

Not so much for the protocol itself, but for what you get with the 
straightforward use of a normal TLS library.

For example, if a developer let the TLS library handle the socket 
connections it seems like it could be smart enough to support 
resumption, but a STARTTLS-based protocol would seem to prevent this. In 
cases where the app code is just passing buffers to the TLS library, the 
TLS stack may not even know the hostname at the time of the Hello 
message exchange.

It's probably not a big deal for most mail protocols, but it might make 
a perceptible difference for a user of IMAP.

- Marsh