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Re: [TLS] Comments on

Adam Langley <agl@imperialviolet.org> Tue, 18 February 2014 02:05 UTC

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From: Adam Langley <agl@imperialviolet.org>
To: Watson Ladd <watsonbladd@gmail.com>
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Cc: Niels Möller <nisse@lysator.liu.se>, "tls@ietf.org" <tls@ietf.org>
Subject: Re: [TLS] Comments on
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On Mon, Feb 17, 2014 at 10:45 AM, Watson Ladd <watsonbladd@gmail.com> wrote:
> Alternatively, we can
> encrypt the entire file as one big chunk and decrypt on receipt.  I've
> still not found a case where one of these doesn't work.

I don't believe that there's any disagreement about the fact that
operating on the file as one, large chunk works, technically.

The problem is that I believe that it results in dangerous APIs. For
example, OpenPGP does this and I was very unhappy about it when
writing this[1] implementation which returns unverified plaintext. I
called the Reader "UnverifiedBody" and put a big comment in there but
I think we should be able to do better. The point of AEADs was to
provide a safer abstraction in the first place, no?

(Niels suggested buffering everything before returning anything and
that's certainly safe. But I feel that it's somewhat anti-social for a
library to do so.)

[1] https://code.google.com/p/go/source/browse/openpgp/read.go?repo=crypto#38


Cheers

AGL

-- 
Adam Langley agl@imperialviolet.org http://www.imperialviolet.org

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