[OTR-dev] OMEMO, PFS

[Ximin Luo]

On 10/11/15 22:15, Greg Troxel wrote:
> So it seems obvious that PFS is not a binary property; presumanbly the
> keys are overwritten (seems hard with flash wear leveling) when new
> messages happen, but there is a perhaps-months "short term key", vs a
> maybe-years "long term key", and PFS or not becomes blurry.
> 

Hi Grey, allow me to refer you to a previous post I wrote:

https://moderncrypto.org/mail-archive/messaging/2015/001877.html

The TL;DR is that to achieve "forward-secrecy for in-transit messages" you need to have some sort of timeout mechanism, as opposed to using cryptographic techniques. I'm not sure if people have engineered this specifically into any protocols, but it would be more of an engineering task than a cryptography task.

X

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