Photo/IllutrationA hardware wallet manufactured by Ledger SAS of France (Provided by Brave Bright Co.)

Alarmed cryptocurrency owners are fueling a sales boom of hardware wallets used for keeping digital money safe in the wake of the recent high-profile heist at Tokyo-based exchange Coincheck Inc.

Major electronics retailer Yodobashi Camera Co. said it began receiving a flood of orders for the gadget, which stores electronic data on cryptocurrencies in its memory, after the theft came to light on Jan. 26. Stock ran out at the chain store just a day later on Jan. 27.

An account, called a “wallet,” must be created on a computer for using digital money, and a “private key” is required for making transactions.

A hardware wallet is a palm-size device for storing digital data on private keys to keep it out of reach of the Internet and potential hackers

Hardware wallets are connected to a computer only while the key is being used. They are usually kept offline, helping lower the risk of data theft through unauthorized access. They could be compared to a safe for storing the cryptocurrency equivalents of a cash card and a registered seal for a regular Japanese bank account.

Most of the available hardware wallet products are intended for use on personal computers.

Coincheck’s customer assets, denominated in the cryptocurrency “NEM,” were connected online when they were hacked and taken. It is believed the theft became possible after a private key was stolen.

The 58-billion-yen ($532 million) heist spread concern among cryptocurrency owners that their assets should be held offline to ensure their safety.

Hardware wallets have also sold out at Brave Bright Co., an authorized, Tokyo-based distributor for Ledger SAS of France, a major manufacturer of the products. Shipments cannot keep up with customer demand, so delivery is not expected before the beginning of March, Brave Bright officials said.