Re: [openpgp] Questions around AEAD packets

Tom Ritter <tom@ritter.vg> Tue, 14 February 2017 16:41 UTC

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From: Tom Ritter <tom@ritter.vg>
Date: Tue, 14 Feb 2017 10:41:13 -0600
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To: IETF OpenPGP <openpgp@ietf.org>, "brian m. carlson" <sandals@crustytoothpaste.net>, Jon Callas <joncallas@icloud.com>
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Subject: Re: [openpgp] Questions around AEAD packets
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On 14 February 2017 at 03:17, Werner Koch <wk@gnupg.org> wrote:
>  3. How can we do early detection of corruption?  When decrypting
>     several gigs we should be able to detect corrupted data after having
>     processed, say, one gig.  Shall such a feature be configurable?
>     Shall we link it to partial length headers.
>
> My ideas here are:
>
>  re 3: The simplest idea would be to use fixed chunks of the ciphertext
>        and either link them together using a counter or the hash of the
>        previous authentication tag.  The packet header would give the
>        length of the chunks in blocks.  It needs to be decided whether a
>        final one-block chunk is okay.

This seems the same question/solution of some sort of authenticated
chunked-streaming mode.  I mentioned this a couple years ago but
didn't get much discussion:
https://www.ietf.org/mail-archive/web/openpgp/current/msg07546.html

-tom