Cold storage
Also · Cold wallet · Hot wallet · Air-gapped
Cold storage keeps Bitcoin keys on a device that never touches the internet, for long-term savings. A hot wallet, by contrast, lives on a connected phone or computer for spending.
The distinction is about exposure. A hot wallet holds keys on a device connected to the internet, a phone or a laptop. It is convenient for daily payments and as exposed as that device is to malware, phishing and theft. Cold storage keeps keys on hardware that is never online, a hardware wallet or an air-gapped machine, and signs transactions passed to it by QR code or memory card.
Cold storage removes the online attack surface but shifts the risk to the human. Keys generated badly, backups made carelessly or recovery never tested are how savings disappear. The usual advice holds. Keep spending money hot and savings cold, and rehearse a full recovery with a small amount before trusting the setup with a large one.
In French · Stockage à froid (cold storage)