A crypto wallet doesn't really "hold" coins the way a physical wallet holds cash. The record of what you own lives on the blockchain itself; what your wallet actually stores are the cryptographic keys that prove you control that record and let you move it. Understanding this distinction is the first step to understanding how crypto wallets, and the risks around them, actually work.
Public and private keys
Every wallet is built around a key pair. The public key (or an address derived from it) is what you can safely share so others can send you assets. The private key is what authorises spending — it's the digital signature that proves a transaction genuinely comes from you. Anyone who gets hold of your private key, or the seed phrase used to generate it, can access and move the assets it controls, which is why protecting it is the central task of using a wallet safely.
Hot wallets, cold wallets, and who holds the keys
A "hot" wallet is connected to the internet, such as a mobile app or browser extension, which makes it convenient for everyday use but exposes it to online threats. A "cold" wallet, like a hardware device or an offline paper backup, keeps keys away from any internet connection, trading some convenience for stronger protection against remote attacks. Separately, wallets can be custodial, where an exchange or platform holds the keys on your behalf, or non-custodial, where you alone control them. The often-repeated phrase "not your keys, not your coins" reflects the fact that with a custodial setup, you're trusting a third party's security and solvency rather than holding the assets directly yourself.
- Never share your private key or seed phrase with anyone, including people claiming to offer "support".
- Keep backups of your seed phrase somewhere offline and secure, not in a screenshot or cloud note.
- Double-check wallet addresses before sending, since crypto transactions generally can't be reversed.
Wallets are simply tools for managing keys and signing transactions — the security and risk depend heavily on how carefully those keys are handled. This is intended as an explanation of how the technology works, not a recommendation to buy or hold any particular asset, and crypto markets carry real risk of loss.
