Bitcoin wallet Xapo has allowed a journalist to visit a secret former military bunker in the Swiss Alps that the company uses to store Bitcoin for its private clients. The bunker, which was constructed in 1947, is claimed to be a secret headquarters of the Swiss army during the Cold War.

In his recent article for Quartz and the World Economic Forum, reporter Joon Ian Wong discussed in detail his trip to the secret military bunker located in a granite mountain in the Swiss Alps. As of late November 2017, the 10,000 square-foot bunker is being operated by the firm Deltalis as a data center.

Detailed features of the Bitcoin vault

In his account, Wong revealed that the first barrier toward the bunker is a 10-foot-high gate. At the entrance, visitors are required to be photographed and fingerprinted after entering the lobby. After which, a visitor is required to enter a “man trap,” which is a bullet-proof glass cylinder that shuts an individual in until an operator opens the door on the opposite side toward the bunker’s main spaces.

The bunker also has a pair of steel revolving doors that require identification (ID) cards to allow access. The doors lead to a 100-meter long corridor. Two red-colored steel doors that can withstand a nuclear blast are located at the end of the corridor.

Behind the doors is another “man trap” leading to a white door where a room the size of a closet is located. The room contains a cooling unit and another door. The door leads to two more rooms, namely, the operator’s room and the “cold room” where the Bitcoin wallet keys are kept. To maintain the security of the keys, the cold room is enclosed with steel slabs to form a Faraday cage to prevent even an electromagnetic pulse (EMP) attack.

According to Xapo’s head of security, they are guarding the vault 24/7 because they are under constant assault by both hackers and terrorists, so they need to implement very tight security precautions to thwart the threats.

“We are under attack 24/7. This is not a race. It is a chess game. You have to think about the opponent’s next movement. You can never relax.”