[guardian-dev] Messaging Moving Forward

[Michael Rogers]

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On 20/05/13 12:18, Timur wrote:
> If someone, situated "close to the chat infrastructure" and able
> to wiretap all conversations would (say, years later) get access to
> a shared secret - they would be able to refit the pseudo-random
> sequence and find out that in all cases A was A and B was B. At
> least in theory.

True - the way we handle this in Briar is to delete the shared secret
as soon as the first temporary secret has been derived, and delete
each temporary secret as soon as it expires. If the shared secret is
strong (eg the output of a DH key agreement), the adversary should
have a negligible chance of guessing it once both parties have deleted it.

Cheers,
Michael

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