op_return outputs can be pruned because they are not spendable. putting a hash on in the witness script data won't make things better (it would actually make them worse) and it definitely doesn't help "block size bloat". I think I'm missing some context, but if you're using op_return purely for timestamping I would recommend using pay 2 contract instead.
On Tue, Aug 14, 2018 at 8:34 PM, Christopher Allen via bitcoin-dev <firstname.lastname@example.org> wrote: > On August 5, 2018 9:11:26 PM UTC, Lautaro Dragan via bitcoin-dev > <bitcoin-dev at lists.linuxfoundation.org> wrote: >>Should we actually be using the BIP process to claim a prefix? > > I recommend against using an op_return prefix, as they allow for transaction > censorship. > > In fact, in our case, where we use an IPFS hash in an op_return, we remove > the IPFS multihash prefix information to post a “bare” SHA256 hash to look > like many other hashes being posted in op_returns, to minimize any ability > for a miner to identify our transaction. The more projects that do this the > better — a form of herd immunity. > > Longer term I’m looking for more responsible ways to publish this hash, for > instance have the hash be in the witness script data, so that it can be > easily purged from nodes that do not wish to preserve it and prevent block > size bloat. However, to do so everyone has to do it the same way, ideally > have it look like any other transaction. I’ve not quite seen a solid > proposal for best practices here. > > — Christopher Allen > > _______________________________________________ > bitcoin-dev mailing list > email@example.com > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > _______________________________________________ bitcoin-dev mailing list firstname.lastname@example.org https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev