At Understanding Bitcoin in Malta, the second day's opening session brought together Blockstream executives to examine what's next for the protocol. Adam Back headed the conversation alongside colleag
At Understanding Bitcoin in Malta, the second day's opening session brought together Blockstream executives to examine what's next for the protocol. Adam Back headed the conversation alongside colleagues Lawrence Nahum and Christian Decker, with Giacomo Zucco steering the discussion. Three upgrades—Schnorr signatures, Taproot, and Sighash Noinput—are expected to move into the protocol. But Zucco wanted to probe whether the path would prove smooth, or whether these changes might encounter obstacles like those that slowed SegWit.
SegWit generated no technical controversy among developers. They supported it. Yet its activation turned into months of political wrangling. Zucco recapped a conversation from the conference's first day. "Yesterday, we discussed the history of SegWit," he said. "SegWit was not a technically controversial improvement. All of the technical people were ACKing SegWit. They were okay with SegWit. But then, they used a mechanism to signal readiness by miners, and miners started to leverage that mechanism in order to vote instead of signal. That created a political drama that lasted for awhile."
Bitcoin Core contributor Eric Lombrozo had flagged this risk. Developers designed BIP 9, SegWit's activation framework, as a concession to miners. Few wanted to use it again.
Back proposed an alternative: BIP 8. He explained the difference. "There's just one small difference [between BIP 8 and BIP 9), which is there's a period for the activation level to reach its threshold, and with BIP 8, if it doesn't reach its threshold, it activates anyway at a fixed date," Back said.
BIP 8, in Back's view, forces miners to get ready and signal without handing them veto power. The system activates in either case once miners have had their window.
Other options existed. P2SH had used a simple date-based approach, now called user-activated soft fork or UASF. That method lacked flexibility and carried risks if the network wanted to retreat from an upgrade mid-process.
Nahum liked where BIP 8 pointed. "[BIP 8] is great because it allows you to go as fast as you can if everyone is on board and activating," he said. "Otherwise, it will take longer, but it will happen anyway."
Zucco raised whether UASF might play a role again. Nahum hesitated. "I don't know if it's going to be like that or not," he said. "You know, I thought SegWit was uncontroversial, but that took a bit. I don't think Schnorr and Taproot are controversial, but we'll see."
The discussion turned to privacy. Both upgrades enhanced privacy, and Nahum believed some would resist. "I'm afraid there's going to be some pushback from people that are not [pro-privacy]," he said.
Back drew a line between privacy and the block size debate. Block size had legitimate tradeoffs worth debating. Privacy didn't. "With privacy, when there have been discussions with [the] user community . . . almost everybody was in favor of privacy on the user side," Back said. "And exchanges are just providing service to users, so if they say, 'we don't take transactions that are private,' users will just switch service providers ultimately. So, it's very unpopular for people to say that they don't like privacy. It would be interesting to push them to see if they are willing do that."
Nahum pressed further: Bitcoin without censorship resistance—strengthened by privacy—becomes a weaker, slower version of PayPal.
Decker saw the environment as transformed. "Most of the people that were shouting and screaming have gone to do their own thing. I don't see that same level of discussion and toxicity in the community like we did with SegWit," he said. "It's quite the contrary, right?"
SegWit had given the protocol something valuable: the ability to improve without hard forks. "SegWit bought us the ability to create some really nice and deep changes without having to hard fork anymore. And so, we now can engineer these really clean and precise and minimal changes to the Bitcoin protocol in a very targeted way without having to carry a lot of the baggage from previous generations of the protocol. I think this is uncontroversial—unlike maybe SegWit. I hear far less opposition to this bundle of upgrades, and I'm pretty hopeful that we can get this done quite quickly," Decker said.
Any of the proposed activation methods—BIP 8, BIP 9, or UASF—would work for what's coming.
