I use a 2-of-3 multisig to secure some of my bitcoin savings. My boyfriend keeps one of the keys but we broke up on Friday. How do I replace his key in the multisig?
– Changing the locks
Hey, I’m sorry to hear about the break up. I hope that it was your choice. If it’s any consolation, at least there’s no hard cap on the supply of potential new matches. This is unlike bitcoin, which is provably scarce. As such, it’s a great idea to use multisig to secure your savings. 👏
When you’re ready to do a “key rotation”, just set up a new multisig wallet using new keys. You can re-use the two that you control if it’s more convenient for you. Maybe you already have robust/redundant storage for these.
When the new multisig arrangement is set up, and you’ve tested your backups, just send your savings to a receiving address there. Sending a small amount first is good practice. As the old setup is a 2-of-3, your own keys will be sufficient for this.

My daughter turns 4 next month and I’d like to set aside some bitcoin for her. She won’t be able to use a mobile wallet for a while yet. What’s a good way of doing this?
– Precious gifter
What a thoughtful gift for the future! You’re thinking of generational wealth already. 💪 There are a multitude of ways that you can set aside some bitcoin for your children. You can send to wallets that you create on their behalf or to securely generated addresses that you make using a Seedsigner or a Coldcard. These entail backing up and later restoring additional wallets though. For the savvy, producing BIP85 child wallets could work nicely. This way, you may be able to restore a wallet for your child and save the day by retrieving the right index number. These are calculated in a deterministic way from a wallet that you already control.
An alternative to the above, and which is much simpler, is to keep a written ledger. You can duplicate this in a spreadsheet that you keep online. In this, you just record the recipient, date, amount, fiat value of the funds set aside. This way, the bitcoin is as safe as your own stack and you can transfer the ownership, even over lightning if your daughter prefers, when she is ready.

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