What is cold storage in crypto?
Taking keys offline shuts out remote attackers. It also makes you the only line of defence against fire, loss and forgetfulness.
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Cold storage means keeping the private keys that control your crypto on something that is not connected to the internet, such as a dedicated hardware device or paper. It protects against online hacking, but the device or backup can be lost, damaged or stolen.
What counts as cold storage?
The SEC's investor bulletin on crypto custody draws the line by connectivity. A hot wallet is connected to the internet — a desktop, mobile or web app. A cold wallet is typically a physical device that is not connected, such as a USB drive, an external hard drive or even a piece of paper. What is actually stored is the private key, not the coins: the coins stay on the blockchain, and the key is what lets you move them.
| Hot wallet | Cold wallet | |
|---|---|---|
| Connected to the internet? | Yes | No (typically) |
| Main strength | Convenient for frequent transactions | Generally more secure from cyberthreats |
| Main weakness | Exposed to online attacks | Can be lost, damaged or stolen, which may mean permanent loss |
Why can losing a cold wallet be permanent?
NIST's blockchain overview explains that if a private key is lost, the assets tied to it are lost too, because it is computationally infeasible to regenerate the same key. If the key is stolen, the thief has full access. Cold storage removes the online threat but leaves both physical ones in place, so a backup stored separately matters as much as the device itself.
Is cold storage the same as leaving crypto on an exchange?
No. Keeping crypto with an exchange or custodian is third-party custody: the firm holds the keys. The SEC bulletin lists the risks that brings — the custodian going bankrupt or being hacked, using customer assets as collateral, or pooling them rather than holding them separately. Cold storage is a form of self-custody, where those risks fall away but responsibility shifts entirely to you. Our guides to hardware vs software wallets and seed phrases cover the practical set-up; a multisig arrangement can spread the risk across several keys.
Questions readers ask
Does cold storage protect against scams?
Only partly. It blocks remote hacking, but if you are tricked into signing a transaction or typing your seed phrase into a website, the funds can still leave. The SEC's advice is never to share private keys or seed phrases.
Do I need cold storage for small amounts?
It is a trade-off between convenience and security that only you can weigh. The SEC bulletin sets out the pros and cons of hot and cold wallets, and crypto wallets explained covers the options.
Cold storage keeps keys away from the internet, which closes off the most common attack. It does not close off loss or theft of the device itself, so it only works with a tested, separately stored backup.
Sources
- Investor.gov, US Securities and Exchange Commission, Crypto Asset Custody Basics for Retail Investors (Investor Bulletin) (2025)Primary source
- National Institute of Standards and Technology, NISTIR 8202: Blockchain Technology Overview (2018)Primary source
Educational content only — not financial, investment, legal or tax advice. Crypto-assets are high-risk and you could lose all the money you put in. Rules differ by country; check with your national regulator. See our risk disclosure and editorial policy.
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