Cold wallet refers to offline wallet. Users usually use offline bitcoin wallet address to send and receive bitcoin, and then use offline wallet private key to confirm the signature. So hackers can't steal the private key of the cold wallet. Because of the offline signature confirmation link, Bitcoin cold wallet is not as convenient and fast to use as hot wallet. The cold wallet does not touch the net, and a brand-new technology mode is adopted to ensure that the cold-end hardware never touches the net. The multiple encryption protection system ensures the core assets and completely eliminates the risk of private key leakage in the cold environment.