Re: [Perc] Double questions

"Paul E. Jones" <paulej@packetizer.com> Tue, 21 March 2017 23:57 UTC

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From: "Paul E. Jones" <paulej@packetizer.com>
To: Eric Rescorla <ekr@rtfm.com>, perc@ietf.org
Date: Tue, 21 Mar 2017 23:57:15 +0000
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Subject: Re: [Perc] Double questions
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Ekr,

>So, does that mean that the original PT/SEQ (as reconstructed from
>OHB) are not used for anything other than to make the decryption work?
>They're totally discarded?

Yes, I think you described it all correctly.  The PT and SEQ are 
necessary only because they were originally there when the transmitting 
endpoint performed HBH authenticated encryption.  Thus, we need those 
original values to properly authenticate the packet when decrypting.  No 
other reason for keeping them.

Paul