 Ricardo asks, why when spending a part of the funds in a paper wallet are you risking losing your remaining balance? What is the best thing to avoid doing that? There are two considerations when you spend from a paper wallet. The first consideration is that if you built the paper wallet securely, you did so on a computer that was offline and isolated from the internet. When you're spending part of the funds on a paper wallet, most of the time what that means is that you either typed, scanned, or sweep the key somehow to a wallet that is online to create that transaction. Which means you just put the private key online. When you put the private key online, it's better to make sure that you spend everything from that paper wallet. Worst case, what you can do is simply make the payment you wanted, spend the amount you wanted, and then send the rest of it to a brand new paper wallet that you've created offline. But what you don't want to do is believe that you still have a secure paper wallet, even though the private key has now been on an online system. That's one concern. The other concern is that many wallets use change addresses in the background. What will happen is you'll do a transaction spending from the paper wallet. The private key and the UTXO that's in that private key on the paper wallet is probably a single UTXO, or a single output as it's known. When you spend from that, unless the amount is exactly what you want to spend, and you want to spend all of it, if you spend less, then your wallet is going to generate change. If it generates change, where does that change go? Well, it doesn't go back to the private key on the paper wallet. It goes to a different address, and that different address is probably a wallet address. Effectively, you've just moved the money from the paper wallet to the wallet you used to spend, part of the amount. If you didn't send the change on purpose to a new paper wallet, you've effectively moved the money online as well, to a key controlled by an online wallet. Again, you're no longer operating cold storage. You've turned it into a hot wallet. Best to spend all of it, and direct any change very explicitly and deliberately to another paper wallet, if you want to keep it secure, and only use a private key from a paper wallet once to move everything. Here's the thing, and just one final thought on that. Because of these complexities, because of how difficult it is to manage paper wallet securely, because of how difficult it is to create paper wallet security, and we're going to talk about that in another question, paper wallets are not as good as hardware wallets for the vast majority of users. Someone who's very technically sophisticated and has a very good understanding of the security implications, and Bitcoin technology, can create a very secure paper wallet. In fact, a paper wallet can be more secure than a hardware wallet if generated correctly. The problem is that the vast majority of users who are likely to use that technology do not understand the technology well enough, and do not have the necessary skills to implement the security correctly. As a result, what they'll end up doing is creating something far less secure. It's very difficult to securely create a paper wallet offline and to maintain that security. The reason hardware wallets are more secure is because they offer ease of use, where the security can be achieved by someone who's not a technical expert. Nikola also asks, how can a paper wallet be generated offline? Well, paper wallets are basically just keys printed on paper, and keys themselves are just numbers. You create private keys by simply picking a number at random, or having your computer pick a number at random. You don't need to be online in order to register keys or produce keys, because no information is exchanged between you and the world in order to produce these random numbers. As I've said before, on a theoretical level, you could flip a coin 256 times, write down the binary digits, and you have a bitcoin key. That's a private key. A 256-bit random number is a bitcoin private key. You could then feed that to a computer program to produce a public key and a bitcoin address, and you've got something that has never been generated online. One of the difficulties with generating paper wallets is, for them to be secure, you have to generate them on a computer that does not touch or has never touched the internet, an air-gapped machine, and then print them to a printer that has no memory and has never touched the internet either. This is an almost impossible task for the vast majority of users. It's almost impossible to create this magical disconnected air-gapped computer and the magical disconnected air-gapped memory-less printer nowadays, which makes it very difficult to implement paper wallets in practice. It's almost like the instructions for creating a perpetual energy machine. Step one, obtain one kilogram of the substance unobtainium. That's all you need, but you can never obtain it. Generating a paper wallet offline. Step one, obtain a computer that has never been online. That's pretty hard. Then initialize that computer with the necessary software without connecting it to the internet, and never connect it to memory, storage devices, or media that come from a computer that has been online. That's pretty much impossible. Now you have all kinds of problems. We know that USB keys can be infected. Ideally, what you'd want to do is generate a read-only medium, such as a CD-ROM, perhaps. It gets very complicated. You're jumping through hoops in order to protect that one computer. You know what kind of computer has never been online and can generate keys for you? A hardware wallet. That's basically what a hardware wallet is. If the instructions for making a paper wallet start with, build your own hardware wallet. When we say, create a computer that has never been online, an air-gapped computer, or configure such a computer, what we're asking people to do is essentially build their own hardware wallet. I would just go with step one, buy a hardware wallet. Step two, write down the seed that appears on the screen, and that's your paper backup. That's all you need. Much easier, actually achievable by most users.