First published 6 March 2019; rewritten August 2026 and expanded in October 2026. The old page was Bitcoin-only and a bit vault-shaped. The idea is broader, and it is a practice: keep the keys that can spend off the computer you use to browse.
Hot versus cold
Hot means the keys live on a machine that also opens websites and email. Convenient, and inside the blast radius of malware and phishing. Cold means the secret that can sign does not sit on that machine. The network still holds the coins either way. Cold storage does not move your bitcoin into a box. It moves the spare key away from the daily driver.
A hardware wallet is the usual middle path. Keys stay in the device. The laptop proposes a transaction. You confirm on a small screen. If you confirm without reading, the laptop is still in charge. Hardware wallets are a practice, not a shopping list.
What actually counts
A hardware device you initialised yourself, with the phrase written down and stored apart from the device. A paper or metal backup of that phrase, kept where a camera and a cloud upload cannot see it. An air-gapped computer that signs and never joins the network, if you truly understand that setup. A multi-person arrangement, where more than one key must agree before a spend, if the people involved have practised. Those are cold in different degrees. The last one fails when the co-signers cannot be found. A backup is an estate plan, not a treasure map.
What does not count
An exchange “vault” or “cold storage” badge. That can mean the company keeps its own keys offline, which is good for them and still an IOU for you. A photo of the phrase. A password manager entry on the same phone as the hot wallet. A PDF emailed to yourself. A device that arrived pre-setup with a phrase already printed by a stranger. A tampered device in the post is rare and real; buy from a channel you can name, and see the hardware-wallet page for the October 2026 reseller case. Writing the words on paper and then leaving the paper in the laptop bag is a label, not a practice.
Paper, metal, PIN, passphrase
Paper fails in house fires and floods. Metal plates exist because of that. Metal does not help if you forget the drawer. Anyone who can see the words can spend. A PIN locks the gadget, not the phrase. A passphrase — an extra secret some wallets add on top of the 12 or 24 words — creates a hidden wallet. It is easy to forget, and an heir who does not know it inherits a monument. If you cannot explain it to your future self, leave it off.
What cold storage does not do
It does not protect you from sending to the wrong address or the wrong network. It does not protect a phrase you already typed into a fake site. It does not make a token safer because the logo is a vault. It does not help if you never test a restore. It does not survive you if nobody else can find the backup.
The drill, while the balance is zero
Write the phrase. Wipe the device. Restore. Confirm the addresses match. Then, and only then, send a tiny amount you can shrug at and confirm it arrives. Store a second copy in a second place you can actually reach. Tell one living person that a backup exists and what not to do with a “support” chat. Do not put the words themselves in an ordinary email.
If the amount would change your year and you will not do that drill, a company account with limits you can survive may fit you better than a brick in a drawer. Information only — not a recommendation to self-custody, and not a shopping list.
