Re: [Cfrg] What groups to use for Diffie Hellman?

Yoav Nir <> Mon, 31 October 2016 19:57 UTC

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From: Yoav Nir <>
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Date: Mon, 31 Oct 2016 21:57:16 +0200
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To: Phillip Hallam-Baker <>
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Cc: jonas weber <>, "" <>, Peter Gutmann <>
Subject: Re: [Cfrg] What groups to use for Diffie Hellman?
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On 31 Oct 2016, at 20:45, Phillip Hallam-Baker <> wrote:

> Based on my conversations with NSA folk, the governing doctrine is 'NOBUS' nobody but us. Introducing a weakness that only the NSA could exploit with hidden knowledge nobody else could discover independently is one thing. Developing a system with a hole anyone can find if they look long enough is not acceptable.

Whatever else he may have accomplished, Edward Snowden proved that NSA hidden knowledge can and does get unhidden. At least to people who failed to learn that from PFC Manning.

So it’s best not to deploy a group that only the NSA can break, even if you are not concerned about the NSA monitoring your data. The next Snowden can make it so that the people that you are concerned about will also be doing it.