Recently, someone asked what a cold wallet is, so I decided to organize my understanding. When it comes to cryptocurrency wallets, many beginners are unclear; in fact, it’s not like a bank account that truly stores money, but a digital container used to store, send, and receive virtual assets.

The core of a wallet consists of three things: private key, public key, and address. The private key is the most critical; controlling it means controlling all assets in the wallet, so it must never be disclosed. The public key is a marker used by miners for verification, and the address is your location on the blockchain, which you can share with others to receive transfers. Simply put, a wallet is like a passport in the blockchain world—your key to entering this space.

Based on whether it’s connected online, wallets are divided into two main types. Hot wallets operate while connected, including exchange wallets, browser plugins (like MetaMask), and mobile apps. The advantage is convenient transactions; the downside is they are more vulnerable to hackers. Especially with centralized exchange hot wallets, although they are nominally yours, control is not truly in your hands—it's like entrusting your assets to the exchange. The FTX bankruptcy was a vivid lesson; many assets were frozen and unrecoverable. Since then, a large amount of Bitcoin has been transferred from exchange hot wallets to cold wallets. Data shows that at that time, 450k BTC were moved out, and some major exchanges even disappeared with tens of thousands of BTC in just a few days.

In contrast, cold wallets are hardware devices that store private keys offline, usually in the form of USB drives or hard disks, and are only connected to a computer when needed. They are much more secure because hackers have no chance to steal private keys online. Common brands include Ledger, Trezor, and CoolWallet, costing roughly $100 to $250.

However, cold wallets also have disadvantages that many people overlook. First, the purchase threshold: you need to buy hardware, and operation is more complex than hot wallets, which is less friendly to beginners. When purchasing, always order through official channels, and check the packaging upon receipt to avoid being tampered with by hackers. Also, if you lose your cold wallet, as long as you remember the private key and seed phrase, you can recover your assets, but this also poses risks for ordinary users.

My advice is to use hot wallets for daily transactions for convenience and speed. But if you hold a significant amount of assets or don’t plan to move them for a long time, you should prepare a cold wallet for storage. Especially during periods of high market risk, keeping assets in your own hands and storing them with a cold wallet is the most reliable approach. Instead of relying on exchange interest rewards, it’s better to have full control yourself, avoiding being caught up in unknown risks.