Oddbean new post about login | logout What is the best option for bitcoin custody within a trust for my family? I just keep our longterm stack on a Coldcard with the keys in safety deposit box stamped on steel but wonder if thats the best option to include within a trust?
SAFE DEPOSIT BOXES ARE NOT SAFE. THEY OFTEN GET DRILLED. IF YOU MUST USE A SAFE DEPOSIT BOX KEEP A COLDCARD IN THERE RATHER THAN STEEL PLATE SO IT IS PROTECTED BY A PIN AT LEAST. OR USE A PASSPHRASE. OR USE MULTISIG. BUT IN ALL SITUATIONS ASSUME THE SAFE DEPOSIT BOX WILL BE COMPROMISED AND MITIGATE THAT RISK. AS FOR TRUST SETUP, I LIKE MULTISIG BEST. GIVES YOU A LOT OF FLEXIBILITY. EX: YOU HOLD TWO KEYS, HEIR HOLDS ONE, LAWYER HOLDS ONE - HEIR AND LAWYER WOULD HAVE TO COLLUDE TO SPEND FUNDS - IF BOTH LOSE KEYS YOU CAN STILL MOVE FUNDS.
I would use SEED XOR and keep one copy with a family member or at a second deposit box. Also male sure you put the steel plates in tamper evident bags; otherwise, you won’t know if the seed phrase has been compromised. If you want a KYC free option for multisig, nunchuk has a great product with inheritance planning that you can also manage through Sparrow if you like that interface better.
Good point on the tamper evident bags. Any recs on good quality ones from reputable source? I assume they are opaque and not transparent too. I like the SDB route but I think Odell has a good point about keeping the steel at home and putting the CC in the box. Ill do that this coming week.
The ones from coinkite are nice because they are sized for their steel plates, but they are pricey. Amazon has good options, and yes get opaque ones. Yeah ideally you would keep a hardware wallet in the security box. You can still put a seed phrase in there if needed if you SEED XOR the seed phrase and use tamper evident bags.
Is SEED XOR difficult to setup already having the wallet established within CC? Ill be honest, always nervous messing with my wallet settings after having everything setup, validated, tested and re-tested.
No, it’s really simple. There are resources from coinkite and BTC Sessions, but it’s a simple process. SEED XOR doesn’t change any settings within your CC or private key. You’re just creating/deriving a multi piece seed phrase from the original seed phrase.