Re: [bitcoin-dev] Committed bloom filters for improved wallet performance and SPV security

[bfd@cock.lu]

On 2017-02-17 11:28, Chris Belcher via bitcoin-dev wrote:
> I think this committed bloom filter idea is very good and much better
> than bip37, but for good privacy for when bitcoin is used often still
> requires certain behavior namely downloading blocks
> from many different peers with new tor circuits.
> 
> Note that I've been dealing with counting transaction subgraphs but
> actually finding them from blocks might also be computationally
> infeasible. Although a Bayesian approach worked very
> well for similar transaction subgraph linking
> [https://arxiv.org/pdf/1612.06747v3.pdf]
> 
> It would also be interesting to analyze what information a spy can get
> if they are missing some blocks that the wallet downloaded.
> 
> For the long term, private and high-volume bitcoin use will be best
> served by off-chain transactions. They will probably be a huge win just
> because the large and public blockchain is such a non-private
> way of doing things.
> 

Thank you for the analysis, this generally matches my views about the
properties offered by the system.

I've generally developed the opinion that BIP37 is effectively unused
by all but a very small number of wallets and services now, setting up
sinkhole nodes in the network to monitor `filterload` commands seems
to back that up.