What's a cold wallet

A cold wallet, as opposed to a hot wallet, is also known as an offline wallet or a disconnected wallet, one of the blockchain wallet types, meaning a wallet in which the network does not have access to the user's private keys. Cold wallets typically rely on "cold" devices (computers, cell phones, etc. that are not connected to the Internet) to secure Bitcoin private keys, using QR code communication to keep the keys off the Internet, avoiding the risk of hackers stealing the keys, but also facing physical security risks (e.g., loss of or damage to the computer). Storing private keys on devices that will not be connected to the network, including printing, hand-copying (paper wallets), or even memorizing them on their own (brain wallets), ensures absolute security during storage. However, the above wallets must still enter the private key into a regular software wallet when making transactions, and the highest standard cold wallets must also be able to sign offline, sending out only signed transactions. The private key is stored in an additional special hardware device, and transactions are signed inside the hardware before being submitted, and as long as the hardware is not cracked, it is absolutely secure. If the hardware device is completely offline and only submits signed transactions, it is also a cold wallet of the highest standard.