General misconception : you can not store your crypto on a USB or anywhere else. How it works :
I was surprised by the amount of people asking: ‘how do I store my bitcoin on my USB?’ or ‘How do I get my crypto off the network?’. Basically, you can not do that. Here is how it works :
Crypto never leaves the network on which they are. They are not physically 'stored' on your USB. You can not physically store Bitcoin on a USB, you can not store Bitcoin (or any crypto) on any device. Any crypto stays on its network.
Ok. So how does it work? If you buy a crypto, you want to put it in your wallet. Each wallet requires a private key (the one that you should never give away). And this private key will generate an address on the network. Then, you can put your funds on this address, thus, in your wallet. Hence, despite being in your wallet, at the end, the funds are (and will always stay) on the network, on your address. So, basically, a wallet is just a software, a window allowing you to communicate and interact with your address (thus with your funds on the network).
With every crypto, everyone can see your funds. You just need a simple address. Go check by yourself on BTC explorer for instance: you can check everyone's funds! But, except checking them, there is not that much that you can do. Why? Because to control the funds, you need the key.
Remember the wallet, this piece of software which allows you to interact with your address? To access it, you need the private key. The private key unlocks the address and allows you to send the funds.
Think about it like your house: I know your home address, where you live, I can see your house. Does it mean that I can enter in and get access to what’s inside? No! I need the key. The same for every surrounding house. A crypto network is like a town with many houses, each containing more or less furniture. And you can only move furniture from house to house. You can not leave furniture on the street or you can not store them on a USB. It has to be inside an house. And the only way to send furniture is to have the key to a particular house, unlock it, and used special guys called miners to move your stuff.
So, to control the funds, you need the private key. And this is what people store on USB, paper wallet or Ledger device : THEIR PRIVATE KEY. If right now I could get access to your private key, I will just log on a wallet using it and I will get access to all your funds. Exactly like if you give me your password from your bank account or the key to your house.
Each crypto requires to install a wallet (and thus to further create Private key). So, if you start to diversify (like most of us) and end up with 25 different cryptos, it will quickly become a burden to safely store all of those different keys…Also, leaving your private key unprotected on your computer or typing it on a computer connected to internet is dangerous. Hackers might be able to see what you are doing and thus, steal your key. This is where hard wallet such as Ledger Nano or Trezor come into play.
A Hard wallet safely store all your keys and will never let them touch the internet. It requires you (your little fingers) to push physical buttons on the Ledger. No hacker can hack your hands. It also automatically manages all your private keys. Indeed, it randomly* generates a MASTER KEY. ***TAKE A DARK VOICE ***A MASTER KEY TO RULL THEM ALL*** which will be used to create all the private keys for your coins. This is a 24 words sequence that you need to store safely. This is the key to all your private keys. If your Ledger get destroyed, buy a new one and enter those 24 words. It will regenerate all your crypto private keys that offer you control on your assets.
*But, computers have hard time to generate random stuff. So, how the Ledger does that? Simply put : when you first switch it on, it will capture the electric noise inside itself and it will put a huuuuge number on this value. This number will be used to create the master key (those 24 words). Because the electric noise is extremely variable and will never be the same ever, your master key will be unique and ‘randomly generated’. So, basically, your 24 words are the representation of the electric noise signature that was captured when the ledger was first switched on. No one will never be able to guess it or generate the same.
And I will repeat this point : to control the ledger (so the master key and the associated funds), you need to push physical buttons on it. No hacker can hack that because you need a physical finger to push it. You can not hack the finger of someone to push a button! So, it’s ultra safe.
So, what are the worst things that can happen? First : your ledger get destroyed and you didn’t properly back up your 24 words. Then your funds are lost. Second : The Ledger company gets hacked (what happened few months ago). Hackers will never get access to your master key (cause as I said, it was ‘randomly generated’ when the hard wallet was first switched on and the Ledger company doesn't know it). But they will have access to some of your personal infos : name, address, email etc. So at best, you will receive phishing email. Never give your key to anyone. Ledger will never ask for your key. At worst, people might break into your house to steal your 24 words. So store your key safely!
I hope this helps to clarify things for newcomers.
TL;DR : If you are new, you should take 5min to read that. If you are an advanced crypto user : go on your way 🙂