reply on: Neat Device for Multisig Steel Backup \ stacker news ~bitcoin

14 sats \ 2 replies \ @fiatbad 20 Jul \ parent \ on: Neat Device for Multisig Steel Backup bitcoin

For a multi-sig, you also have to have ALL xpubs for ALL seeds in the multi-sig.

Are just the xpubs enough?

Say I have a 2 of 3 multi-sig using 3 ColdCards with each seed word stored on a separate Seedplate (from CoinKite).

Then, I store the xpub from each ColdCard on a single USB thumb drive. So there are 3 xpubs on one thumb drive.

With only the 3 SeedPlates and the 3 XPUBS, do I have everything required to restore the multi-sig?

14 sats \ 1 reply \ @nerd2ninja OP 20 Jul

I have to comment on the seemingly strange company shilling in your question, but to answer:

If you have ALL seed phrases, you don't need all xpubs. You can generate the xpubs from the seed phrase and derivation path. However, if you have only 2 of the 3 in a 2 of 3 (say the third one was lost or stolen aka an availability issue) then you need all three xpubs.

xpubs and derivation paths are all about helping you find which utxos belong to you that you can sign. There are other ways you could accomplish that end, but they are more complicated (like storing every Bitcoin address you have ever sent coins to, or storing PSBTs) than just backing up derivation path, script type and xpubs.

14 sats \ 0 replies \ @fiatbad 21 Jul

I guess I could have worded my question better. I should have just asked:

"Do the xpubs contain the derivation paths and script types?"

When I open the xpubs in a text editor, the derivation path appears to be there.

So, if I store the xpub from each hardware wallet on an external HD, and then store seed phrase for each on steel, am I good?

BTW, thanks for this post. I'm planning to get a SeedHammer soon because it seems to be the best option. Will it play well with a fully ColdCard multi-sig setup?