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Re: [TLS] ChaCha and IVs

Dr Stephen Henson <lists@drh-consultancy.co.uk> Tue, 04 March 2014 20:48 UTC

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Date: Tue, 04 Mar 2014 20:48:14 +0000
From: Dr Stephen Henson <lists@drh-consultancy.co.uk>
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Subject: Re: [TLS] ChaCha and IVs
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On 04/03/2014 20:22, Dr Stephen Henson wrote:
> On 04/03/2014 19:44, Wan-Teh Chang wrote:
>>
>> I researched the FIPS validation of AES-GCM recently. My conclusion
>> was that using an externally-provided nonce/IV for AES-GCM is
>> acceptable for FIPS 140-2 validation.
>>
> 
> I'd be interested to know if that has changed in the last few years. We had to
> go to quite a bit of trouble specifying how the IV was generated in some
> detail... an experience I'd have gladly avoided.
> 

Weird... I went back through my old notes and found a reference to FIPS140-2
Implementation Guidance (IG):

http://csrc.nist.gov/groups/STM/cmvp/documents/fips140-2/FIPS1402IG.pdf

In section A.5 are some comments about AES-GCM including this:

	1. The external generation of the IVs is not allowed.

Steve.
-- 
Dr Stephen N. Henson.
Core developer of the   OpenSSL project: http://www.openssl.org/
Freelance consultant see: http://www.drh-consultancy.co.uk/
Email: shenson@drh-consultancy.co.uk, PGP key: via homepage.

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