In a single sig wallet, it's sufficient simply to know the 12 or 24 word seed phrase to recover the funds. This makes for a really nice user experience, since it's relatively easy to write them down on paper.

I thought that a 2-of-3 multisig was similarly simple, but it turns out that's not the case. Intuitively, as a user, I should only need 2 of the 3 seed phrases to recover any funds, but in reality, at least on Blue Wallet, you also need a "backup coordination file," which consists of all 3 public keys, the derivation path, and the script format. Without it, your funds are lost if you lose one of the 3 seeds.

This isn't a great user experience, especially if you're trying to explain a multisig vault to one of your grandparents. Writing seed phrases down on paper is easy for most people to understand, but having to download a bespoke file and securely save it on a thumbdrive makes everything more complicated, and frankly unintuitive. This inevitably scares people off, I fear, from what is otherwise a great way to make people more comfortable with cold storage.

Keeping the backup file on a third party provider, like Unchained, isn't really a solution, because at the end of the day, Unchained still recommends that you backup the data yourself, which is confusing and somewhat cumbersome.

The only long-term robust solution I think is for the backup file to be stored onchain, ideally in an encrypted fashion such that you only need 2 of the 3 private keys to recover the data. This could be done relatively cheaply in witness data, like a taproot inscription, and it would mean that the average user only ever needs to worry about maintaining access to 2 of the 3 seeds. In the event the multisig vault needs to be recovered, the user only needs to provide 2 seeds, and perhaps a date range of when the vault was created, and software can scan the relevant witness data and recover the file.

Do you think a scheme like this could work? Curious if others find this to be a relevant problem.