Paper wallet

A paper wallet is created by generating a key pair, ideally on an offline computer, and printing the private key and its public address on a sheet of paper. Funds are sent to the address, and the paper is stored somewhere safe. To spend, the owner imports or sweeps the private key into a software wallet, which moves the whole balance at once.

In Bitcoin's early years, paper wallets were a cheap way to keep coins off internet-connected machines, and they were handed out as gifts or used at conferences. Hardware wallets and seed phrases have since replaced them for most people, because they offer offline signing without exposing the key whenever money moves.

The weaknesses are many. Generator websites can be malicious or compromised, printers and their memory can keep a copy, and paper burns, fades or gets thrown away. Spending only part of the balance from an imported key can send the remainder to a change address the paper does not control if the wallet software is used carelessly. Old paper wallets may also use legacy address formats that cost more in fees.