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Re: [TLS] 0.5 RTT

Karthikeyan Bhargavan <karthik.bhargavan@gmail.com> Tue, 23 February 2016 22:01 UTC

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From: Karthikeyan Bhargavan <karthik.bhargavan@gmail.com>
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Date: Tue, 23 Feb 2016 14:01:28 -0800
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Subject: Re: [TLS] 0.5 RTT
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> Won't a downgrade be detected by the client when it fails to decrypt
> the server's data? 

The main downgrade concern, I think, is for the 0.5-RTT data’s confidentiality; i.e. it may have been sent encrypted under a broken cipher.
You’re right that the client will not accept this data because the handshake hashes (mixed into the key) would not match.

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