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Re: [TLS] Tickets after key update/post handshake auth

Eric Rescorla <ekr@rtfm.com> Fri, 16 March 2018 16:37 UTC

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From: Eric Rescorla <ekr@rtfm.com>
Date: Fri, 16 Mar 2018 16:36:25 +0000
Message-ID: <CABcZeBNMFs0mGOkSq+oqw2LCDhZxfTzbrCWPYozVihiPED+Hxg@mail.gmail.com>
To: Matt Caswell <matt@openssl.org>
Cc: "tls@ietf.org" <tls@ietf.org>
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Subject: Re: [TLS] Tickets after key update/post handshake auth
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On Fri, Mar 16, 2018 at 4:19 PM, Matt Caswell <matt@openssl.org> wrote:

> What is reasonable behaviour for a client to do with any tickets it has
> previously received following a key update or a post-handshake
> authentication? Should those old tickets be now considered out-of-date
> and not used?
>

There is no good reason to discard tickets received post KeyUpdate. The
KeyUpdate
has no impact on their security.

It's probably reasonable to discard tickets received after Post-Handshake
Auth if a new
ticket is received, as that ticket might incorporate the client's
authenticated identity. Otherwise
I wouldn't bother.

-Ekr


> Matt
>
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