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Author: Admin | 2025-04-27
From just a news item to me. RustBitcoin now has BIP324 support, is that right?Mike Schmidt: Just the encoding and decoding of the messages.Mark Erhardt: Okay. So, it will not use it yet at the network layer?BDK #1789Mike Schmidt: No. BDK #1789, which changes the default Bitcoin transactionto version 2. Transactions signaling version 2 were defined in 2015 aroundenabling OP_CHECKSEQUENCEVERIFY (CSV) for relative timelocks, which you canrestrict the age of the output being spent. In our summary, we noted only 15%of the transactions were still using version 1. So, version 1 type wallets havea smaller anonymity set and thus worse privacy. BDK already did have version 2support before this PR and this PR simply changes the default version to version2 moving forward.Mark Erhardt: This is a little interesting. I saw that, I looked at somestatistics and it had been down to almost 90% version 2 transactions. Andrecently, there was a resurgence of version 1 transactions. So, someone that’sdoing more transactions now is using v1 still. And, well, I don’t know. It’sstill valid. If you’re not using CSV, you don’t need version 2, but it was downto below 15%, now it’s almost 25% again. It’s kind of funny to see.Mike Schmidt: There was also an issue that I thought was interesting thatpartially motivated this PR and it noted, and I’ll quote a portion of the issue,“It’s likely that less than 15% of version 1 transactions are created by oldwallets. It is also likely that BDK would be used with newer output types. Ifthese two assumptions hold, it would make it possible to identify a BDKtransaction with near certainty”. Murch, you agree with that assessment?Mark Erhardt: Yeah, the combination of fingerprints is probably – like, 15%of all transactions doesn’t sound like that small of a number, but then incombination with other fingerprints, like P2TR or P2WPKH and version 1, or someother combinations, would probably make it a pretty useful fingerprint. I alsonoticed just now, I’ll have to tell 0xB10C that there’s only version 1 andversion 2 in this chart for transaction versions.Mike Schmidt: Ah, yes.Mark Erhardt: We have version 3 now, yeah?Mike Schmidt: That’s right, yeah. Well, I thought we had TRUC(Topologically Restricted Until Confirmation)!Mark Erhardt: Yeah, but TRUC transactions, yes, that is correct. TRUCtransactions is the construct or abstract term for what we’re doing, but thetransactions that use the TRUC rules signal version 3 or use transaction version3 in order to indicate that they would like to be restricted topologically. So,they should show up as version 3 transactions.BIPs #1687Mike Schmidt: BIPs #1687 merges the sending silent payments with PSBT’s BIPand assigned it the BIP375 number. Murch, unpack that one for us.Mark Erhardt: All right. So, usually when you do a PSBT, you have multipleindependent parties, or one party that uses multiple devices like an AirGapsigner, or… Anyway, we’re talking about a tool to keep track of an incompletetransaction through the various stages of it being incomplete. One side isprobably putting together the framework with what outputs are being created,what inputs are
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