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Re: [openpgp] Followup on fingerprints

Vincent Breitmoser <look@my.amazin.horse> Wed, 29 July 2015 23:34 UTC

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From: Vincent Breitmoser <look@my.amazin.horse>
To: Phillip Hallam-Baker <phill@hallambaker.com>
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Date: Thu, 30 Jul 2015 01:34:09 +0200
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Subject: Re: [openpgp] Followup on fingerprints
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On 29 Jul 2015, Phillip Hallam-Baker wrote:
> If we are doing ECC, it is quite practical for someone to generate
> 2^50 keys and then pick the two that match in the first 100
> bits. This can then be used for attacks, particularly if the keys
> are not enrolled in some sort of blockchain.

What sort of attacks are we talking about here?

> The other bit I left out is the idea of compression. The idea here
> being that the person generating the key looks for a fingerprint
> that has 0s for the first n bits. Then the fingerprint starts with a
> version number that says 'the first 32 bits are 0s' or whatever.

What do you mean here by "looks for"? Doesn't this effectively just
limit the bitsize of used fingerprints?

 - V

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