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A comment on Listen to Your Key: Towards Acoustics-based Physical Key Inference. Parent comment

Re:Listen to Your Key: Towards Acoustics-based Physical Key ... by hipokampa on Wednesday August 19, 2020 @07:02AM (#24209088)
You would have to be very unlucky to take 34 minutes[1]. After mere 75 tries (seconds) the chances are >50%.

[1] https://en.wikipedia.org/wiki/Birthday_problem

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Re:Listen to Your Key: Towards Acoustics-based Physical Key ... by speakeron on Wednesday August 19, 2020 @08:32AM (#24209720)
The birthday problem isn't applicable here, because you're trying to match a specific combination rather than looking for any matching pair. So the average number of attempts needed is indeed 4096/2.

This is the same as the difference between a preimage (specific input) attack and a collision (any pair of inputs) attack on a hash algorithm[1].

[1] https://en.wikipedia.org/wiki/Preimage_attack

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