[Bitcoin-development] Bloom bait

Alan Reiner etotheipi at gmail.com
Sat Jun 7 19:44:07 UTC 2014

On 06/07/2014 07:22 AM, Mike Hearn wrote:
> You can send different bloom filters to different peers too, so I'm
> not sure why you're listing subsetting as a unique advantage of prefix
> filters.

Please let me know if we've gone down this path before, but it would
seem that the more different bloom filters you create, the more
information you give away.  It would be most useful to create a single
bloom filter that captures every address you ever intend to use (say a
look ahead of 1000 addresses), and then only ever communicate that. 
Once people see multiple filters that you produce, they can start
looking at the intersection of them to reduce the identity space.  I
would expect that after enough bloom variants, they could figure out a
perfect subset of blockchain addresses in your wallet.  (I suppose you
could intentionally select an extra 20% addresses to include in every
bloom filter, but it's a hack).

Similarly, if you keep updating your bloom filter to include more
addresses, the difference in what passes through the previous one and
the new one gives away information about new addresses you created.

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