Cold storage

In cold storage, keys live on hardware that never goes online. Signing means bringing a transaction to the device, approving it by hand and carrying the signature back. Remote attackers have nothing to reach.

The cost is speed and effort. Cold storage suits reserves that move rarely. Day-to-day deposits and payouts need something that can sign without a person carrying a device, a hot wallet with strong controls.

A common split

• Cold: long-term reserves, moved a few times a month at most.
• Hot: the float needed for payouts, kept as small as operations allow.
• A rule for when and how the hot wallet is refilled, and who approves it.

On Valtu

Two parts of Valtu are cold: the key ceremony that created the production keys ran on a machine that has never been connected to a network, and the backup of those keys is split with Shamir secret sharing and held offline. Day-to-day wallets sign online, inside hardware enclaves. If part of your treasury belongs in cold storage, keep it in a cold setup of your own and hold in Valtu what operations need.