 The next question comes from Miyagi and it's about using multi-signature techniques to manage your Satoshis. Blockstream green is one of the multi-signature techniques but requires re-deposits once in a while because of end time locks. This is a bit counter-holding, meaning that if you use it for cold storage, you're going to have to keep moving your coins every now and then. CASA has a paid service for multi-sig using physical separation. This appears to be robust and well-thought-out option, says Miyagi. Electrum gives you multi-sig options, but it is an advanced feature requiring skill. Do you recommend multi-sig for the commoners, especially for crypto-savings, meaning cold storage, and what would be a good solution for them? That's a difficult question, Miyagi. Now, I'd like to separate multi-sig into fundamentally two different categories. A lot of what you've described, the services you've described, are multi-party multi-sig. That means you have some kind of multi-sig scheme, a K of N scheme, where out of N keys, K are required, the quorum, K are required in order to sign a transaction, but the participants in the multi-sig are different parties. So, you have one, two, or three of the keys, five of the keys, whatever. And another company or participant has another set of keys, and you have to combine some of yours and some of theirs, or all of yours if you have the cold storage keys. In all of those schemes, obviously, the company that has the third party that has some of your keys usually has a minority of the keys, meaning they do not have enough keys on their own to make a transaction, which is how you maintain control your keys, your coins, you maintain custody and sovereignty over your funds. You mentioned Electrum at the end, and with Electrum or any basically wallet that allows you to construct your own multi-sig scheme, you could quite easily create multi-party multi-sig, where you give or have others generate some of the keys of your multi-sig scheme. For example, a friend, a trusted relative, an attorney, or something like that. Although, generally speaking, it's very difficult to find people you can both trust and know how to use keys. And the more they know about how to use keys and about crypto, the less I trust them, honestly. And the more I trust them, the less they know about keys. It's a bit of a conundrum. The other thing you can create, however, is not multi-party multi-sig, but multi-factor multi-sig. Multi-factor multi-sig is where you have all of the keys that are participating in the multi-sig system, but you keep them on different devices and formats. Meaning that, for example, you might have one key on your mobile smartphone, one key on a hardware wallet, one key in cold storage, and do a two or three. So, effectively, it takes a signature from your hardware wallet and a signature from your smartphone under normal circumstances in order to execute a transaction. But you also have a backup, which you have maybe in the form of a mnemonic phrase stored somewhere securely, or even a hardware wallet with a mnemonic phrase loaded stored somewhere securely, and you only bring that out in an emergency. For example, if you lose the key that's on your mobile device or your other hardware wallet. Now, such schemes can give you a good balance between backup, meaning resiliency to disasters, damage to your phone, loss, etc., and at the same time give you some cold storage capability. Now, you may have noticed in this case at least two of those keys are readily accessible to you, which means that doesn't really protect you against coercion. So someone coming with a $5 wrench and forcing you to give up forcing you to give up your funds. The bottom line is that all of these schemes schemes require a careful analysis of the threat model. What exactly are you trying to protect against? Are you trying to protect against loss of funds due to an accident, damage to devices, loss of memory, or something like that? That's a difficult risk to protect against and a lot of people underestimate that risk. As a result, they end up losing funds all the time because they do something too complex with not enough resiliency and backup. Are you protecting against theft by a sophisticated opponent who knows you have crypto and is targeting you specifically? Again, a difficult threat, which most people overestimate, leading them to creating complex solutions without enough backup, but still a real threat. Are you dealing with risks of software bugs and things like that where your crypto is stolen by atrocious virus malware, some vulnerability in the software, where it's easy and not targeted? It's an attack against everyone who has crypto or everyone who has that software or everyone who can be found to have that software. You have to balance these risks carefully. For cold storage, I would recommend using a straightforward hardware wallet that is backed up with a mnemonic phrase in at least two different locations and keeping those mnemonic phrases secure for additional security, adding a passphrase that you also need to backup in addition to your mnemonic phrase and not going with multisig because multisig is often too complex for people and can lead to losses because you didn't plan the multisig carefully enough. Multisig for cold storage is something that people with either very, very large funds, lots of assets would do or very complex security arrangements, especially multi-party multisig is usually reserved for people who need separation of duties and governance in the case of, for example, running a corporate fund where you don't want one person to be able to run away with the money. Multi-factor multisig is something that individuals with very high security requirements might use and they might use it in order to protect themselves from loss as well as security attacks against a specific software or hardware system. So by differentiating the software and hardware that's used for the different keys, you ensure that vulnerability in one doesn't compromise the entire system. I would probably go with a very, very simple two of three multisig, multi-factor system with three mnemonic phrases, two of them perhaps loaded on hardware wallets and used for cold storage, but the requirements for that are pretty high and building something like that is complicated. You would do that, of course, with something like Electrum and it would offer you a very high degree of security, but it's difficult to execute. Most people don't need that. A simpler option would be a multi-factor multisig using a mobile smartphone solution and a hardware wallet, again, using software like Electrum. Now, there are some technologies that are making it easier to do this. One of these technologies is called Partially Signed Bitcoin Transactions or PSBT that is a format for exchanging a partially signed transaction between multiple devices in a common format. So if you can find wallets that support PSBT, you can construct multi-factor multisig across different software devices that are compatible. Again, this is really not very mature technology and there are all kinds of problems you can run into if you're a newbie. So the bottom line is this is difficult to do. Most people don't need it and I would go with something simpler, honestly. If you think about some of the other questions we answered today, for example, inheritance, you've got to consider not only how difficult this will be for you to execute, but now imagine your non-technical uncle or nephew who's trying to figure out what you did and unravel that scheme in order to recover something because you've passed away. That becomes 10 times more complex and at that point you're more likely to have your funds lost forever.