Since online wallet represents a network-end product, there exist some safety-related risks in itself. For “U-disk” hardware wallet (e.g. leger, trezor, and keepkey), due to the need to connect computer through USB interface in its use, there is safety risk amid computer networking; and it becomes inconvenient for Chinese people, because of the full-English interface. Besides, since the use of local wallet operation is also quite cumbersome, and cannot be used anytime and anywhere outside, it reports low flexibility, leaving it gradually marginalized. As the off-line hardware wallet in real sense, ColdLar wallet is divided into two parts: cold-end hardware wallet and hot-end APP. Cold-end does not contact the net at all. After the cold-end builds the transaction, it scans the cold-end transaction with APP for QR code broadcasting transaction.This mode can completely eliminate the exposure to hackers.