Re: [TLS] Fwd: New Version Notification for draft-tiloca-tls-dos-handshake-00.txt

Benjamin Kaduk <bkaduk@akamai.com> Sun, 09 July 2017 16:34 UTC

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To: Eric Rescorla <ekr@rtfm.com>, Marco Tiloca <marco.tiloca@ri.se>
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From: Benjamin Kaduk <bkaduk@akamai.com>
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Date: Sun, 9 Jul 2017 11:34:22 -0500
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Subject: Re: [TLS] Fwd: New Version Notification for draft-tiloca-tls-dos-handshake-00.txt
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On 07/09/2017 08:33 AM, Eric Rescorla wrote:
>
>
>
>     Also, it considers Section 7.4.1.4 of RFC 5246, i.e. the same
>     extensions SHOULD be included in case of request for session
>     resumption.
>
>     This also led to the design in the draft (i.e., the HMAC computed
>     by the client and the provisioning of a session key K_S), so that
>     the client does not require to contact the TA again in case of
>     intended session resumption.
>
>
> It seems like if this is really important, the TA could just give the
> client some small
> number of tokens on initial contact.
>

I wonder if the desired properties could be obtained by having the TA be
a Kerberos KDC that only issues [Kerberos tickets targetting the TLS
server's Kerberos principal] to [Kerberos clients that are authorized to
speak TLS to the TLS server].  Then the TLS extension could just hold a
Kerberos authenticator that binds to the client random and the client
can reuse the kerberos ticket until it expires.

-Ben