Automated Bitcoin Core installation and the Assumeutxo project

[darosior]

Liana requires a connection to a running Bitcoin Core instance to operate. Most users don't run Bitcoin Core on their machine, and having to install many moving pieces is a friction to the UX.

We could imagine the GUI installer would download and install Bitcoin Core itself at the click of a button from the user. But then, the user would not be able to use the wallet before IBD is done.

Here enters the assumeutxo project: bitcoin/bitcoin#15605. If the user is not able to setup Bitcoin Core themselves, the temporary trust (until background IBD completes) of assumeutxo could be reasonable. Anyway for these users it's that or using a random public Electrum node so...

What do you think?

[kloaec]

I'm not too sure how to make it best, I guess if Core isn't detected running, a message could pop up asking to run it or install it.
IBD is long yes. AssumeUTXO is "better" than random Electrum, but if/when we have electrum we can ask the user what they prefer as failover during IBD:

• Wait for full verification
• Use AssumeUTXO
• Use Electrum during sync time

[darosior]

Another note: Specter and BTCPay distribute snapshots of data directories for this usecase. I think it's insane and we shouldn't do that, but wanted to mention it still.

[darosior]

Another issue: we can't just download a binary and run it on the user machine. At least not under MacOS (and probably Windows too). And bundling bitcoind by default would be insane.

EDIT: actually if the binary is notarized it should work.

[darosior]

Partial support for Assumeutxo was released in Bitcoin Core 26.0. It's still not usable, and even less so with a wallet.