Coldkey and hotkey

A Bittensor wallet uses two kinds of key, and they do different jobs.

The coldkey owns your funds. It signs the actions that involve money: sending TAO, staking and unstaking, registering, and owning a subnet. Because it controls everything of value, it should be kept as safe as possible. People who hold a lot often keep it on a hardware wallet or an offline device.

The hotkey is a working key. Miners and validators use it to take part in subnets, for example to submit scores. It is meant to live on a computer that is always running, so it is less protected.

A leaked hotkey cannot move your TAO. It can still cause harm, such as submitting bad scores under your name, so it is not something to share either.