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Re: [TLS] Clarifications and questions: TLS1.3 - Static RSA and AEAD

Jakob Breier <Jakob.Breier@rwth-aachen.de> Tue, 27 May 2014 14:18 UTC

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Date: Tue, 27 May 2014 16:18:22 +0200
From: Jakob Breier <Jakob.Breier@rwth-aachen.de>
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Subject: Re: [TLS] Clarifications and questions: TLS1.3 - Static RSA and AEAD
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On 05/27/2014 04:00 PM, Watson Ladd wrote:
>> >They will be in trouble. However, presumably if they have a place to store
>> >their private key, they can somehow store other random data there that
>> >they use to generate random values, no?
> But then they can store an incrementing counter for use with AES with
> a fixed key as a RNG. I don't see the problem here.

Even better, if there is some memory that can be securely erased, you 
could retain PFS via something like
r_(j+1) = HMAC(longTermKey, r_j || counter )
where the cache of the current random output r_j will be overwritten 
with r_(j+1).

Regards,
Jakob Breier

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