Definition
A cold wallet is a wallet arrangement designed to keep private signing keys outside internet-connected systems. It can involve a dedicated hardware signer or a properly maintained offline computer. Cold refers to key isolation, not to the coins themselves: asset balances are still recorded on the blockchain and can change without the signing device being online.
How It Works
An online interface can prepare an unsigned transaction and transfer it to the offline signing environment. After the user checks the details and approves it, the resulting signature or signed transaction is returned for broadcast. The private key should not need to leave the protected environment. Specific transfer methods and protections depend on the device; not every hardware wallet is physically air-gapped.
Key Considerations
Cold storage reduces certain online attack paths but does not prevent an owner from approving a malicious transfer. Verify recipients and permissions on a trusted display where available. Secure the recovery backup separately: anyone who obtains the required recovery secrets may bypass the original device. Importing the same seed into an online wallet exposes that key set and undermines its cold status. Loss, theft, damaged backups and compromised setup processes remain relevant risks, so recovery arrangements matter as much as disconnection.