{"type":"rich","version":"1.0","author_name":"npub1xqshkqv2g7uea4xzqwvmgjcz7u8vfavw6aazs999v0azsv3w7u3qpymc2p","author_url":"https://nostr.ae/npub1xqshkqv2g7uea4xzqwvmgjcz7u8vfavw6aazs999v0azsv3w7u3qpymc2p","provider_name":"njump","provider_url":"https://nostr.ae","html":"📅 Original date posted:2015-02-20\n📝 Original message:Hello Adam,\n\nOn Fri, 20 Feb 2015, Adam Back wrote:\n\n\u003e So I was wondering what about changing to committing a bloom filter of\n\u003e the addresses in the block.  Its seems surprising no one thought of it\n\u003e that way before (as it seems obvious when you hear it) but that seems\n\u003e to address the privacy issues as the user can fetch the block bloom\n\u003e filters and then scan it in complete privacy.  (Someone appeared on\n\u003e bitcoin wizards IRC a while back and made this observation.)\n\nI have heard this idea of inverting the bloom filter before (possibly in \n#bitcoin-wizards), and as I see it it would indeed improve the privacy. \nApart from privacy it would also lower the burden for nodes. A block scan \nwith bloom filter is effectively a cheap DoS on a node.\n\nIn addition to that it will also avoid the 'transaction withholding \nattack' that is possible with the current bloom filtering, at least if the \nfilter is e.g. committed to in the block header.\n\nThe drawback would be overhead - the bloom filter per block will have a \nsignificant size (to avoid false positives), and the client would have to \nfetch entire blocks that have its transactions in it.\n\nI don't think that is so bad in practice, after all the % of blocks that \nwill have transactions for a given wallet will generally be low, so the \nblock size is amortized in a way. Of course, if the block size would be \nincreased this would become worse.\n\nWladimir"}