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Re: [TLS] ChaCha and IVs

Nico Williams <nico@cryptonector.com> Thu, 06 March 2014 01:48 UTC

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Date: Wed, 05 Mar 2014 19:48:10 -0600
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From: Nico Williams <nico@cryptonector.com>
To: Bodo Moeller <bmoeller@acm.org>
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Cc: Stephen Kent <kent@bbn.com>, "tls@ietf.org" <tls@ietf.org>
Subject: Re: [TLS] ChaCha and IVs
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On Wed, Mar 5, 2014 at 7:37 PM, Bodo Moeller <bmoeller@acm.org> wrote:
> Right -- sorry, when I wrote the above, I only meant a check when
> *en*crypting. *De*cryption is normally expected to have to handle
> potentially arbitrary explicit IVs, anyway: for example, if encryption uses
> random IVs, decryption will just have to accept these -- you wouldn't be
> generating random IVs in the decryption module too :-).

Again, the module might check a sequence number window of its own.
And on the encryption side you should want a threaded program to be
able to encrypt out of order.  DTLS' out of order functionality is not
(or need not be) just in case the transport reorders.

Nico
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