Topic: Casa Keymaster? (Read 224 times)

I have been using their service and I haven't had any problems.

Hi there, I'm the co-founder and CTO of Casa! Just stumbled across this thread and figured I'd chime in to address concerns.

To start off, we've outlined our threat model and design decisions here in our Wealth Security Protocol: https://docs.keys.casa/wealth-security-protocol/.


This is a valid concern, and our Gold tier is "bring your own hardware" while our premium tiers include devices. We are authorized resellers for both Trezor and Ledger. Users are welcome to buy directly from them if they wish to further reduce supply chain risk!


You can certainly skip backups if you want, though we believe this is the best trade-off between convenience, security, and redundancy for the average user. Advanced users may be capable of securing seed phrase backups, but we believe this is asking too much of casual / mainstream users.


There are so many risks that go unstated when people say "store your seed phrase in a safe place" that it's laughable. I've performed extensive tests that show many seed backup devices are actually can't withstand common house fires, for example. And if you put a seed phrase in a safety deposit box it's still vulnerable to the bank itself and to state actors that can coerce the bank. We do recommend storing a coldcard in a safety deposit box, however, as the hardware then provides another layer of security against insider / state level attacks.

TL;DR you may not agree with our thesis that the average user isn't capable of securing seed phrases against all of the attacks that our security model protects against, and that's OK.


This is a misunderstanding - the Emergency Lockdown feature is not available to 2-of-3 multisig accounts, only to 3-of-5 accounts. When activated on a 3-of-5 account they still have a sufficient threshold of keys to route around our service without the Mobile Key if necessary. We take great care to ensure that Casa can not unilaterally create or block transactions; we strive to eliminate any single points of failure, including our own service. For further clarification you can view our step-by-step recovery guides at https://walletsrecovery.org/recovery-docs/casakeymaster-recovery.html

Also worth noting that for 2-of-3 we support using 2 hardware devices and no mobile key, which I believe alleviates several of the concerns you voiced.

I'm not on this forum often; feel free to direct further questions to me via any of my verified accounts listed on https://keybase.io/lopp or ask our support team at [email protected]!

I am not a user, but I looked at their website just now. They look very similar to BitGo, and have a similar business model from an operations perspective.

They appear to be a new company, receiving only $2.3 Million in seed money in March 2018.

Based on my reading and understanding of their website and documentation, you will use their App on your phone that serves as one of three signing keys to a 2-of-3 multi signature wallet. Two of the signing keys will be on a hardware wallet and on your phone. They will have the third signing key, but it is unclear how they sign any transactions for you.

I found some security practices I believe are bad reading their FAQ
-If you sign up for one of their paid plans, they will ship a hardware wallet from their office. Hardware wallets such as Trezors and Ledgers should be received directly from the manufacturer.

-Backups of signing keys intended to be on your phones App will be stored in the cloud:
I prefer to not have any backups stored on my iCloud account, even if encrypted.

-They instruct users to not keep backups of a hardware recovery seed:
You should write down your recovery seed when generating a seed on a hardware wallet, and store it in a safe/secure location, preferably in a safety deposit box, or a fire safe in your house.

-They can restrict access to your money:
I believe this to mean they have the ability to restrict your access to your mobile key available on their App. It does not appear they can access this key, but you will be unable to spend any coin if they restrict access to this key. They would still have access to the third key. This will leave you vulnerable to them restricting access to your mobile key unless you sign a transaction sending some coin to them with your hardware key.

My opinion is you are better off buying a hardware wallet to secure your coin. If you want to use a multi sig setup, you can buy multiple hardware wallets, from multiple manufacturers if you wish.

I've come across this new service called Casa keymaster. I'm aware that some of the subscriptions offered there are probably meant for businesses and not the average user but has anyone used them before and could give us a review and tell us whether it's worth it or not.