Exclusive: Inside a Swiss nuclear bunker’s secret Bitcoin vault

It sounds far-fetched, but it’s true. A vault successful a concealed atomic bunker successful nan Swiss Alps protects a important magnitude of Bitcoin. 

Cointelegraph visited nan installation to spot really multiparty computation (MPC) shards stored successful bunkers are utilized to supply bleeding-edge information to 1 of nan world’s first Bitcoin (BTC) banks. 

Every Bitcoiner knows nan building “not your keys, not your coins,” but you can’t support hiding your hardware wallet aliases seed building nether your mattress forever. With an estimated 2 cardinal BTC irrevocably lost, really and wherever you shop your BTC remains 1 of nan astir challenging aspects of owning nan integer asset.

— Gareth Jenkinson - Token2049 🦙 (@gazza_jenks) September 26, 2024

For some, holding their BTC connected an speech is simply a consequence they’re consenting to take. Others move their Bitcoin into acold storage. 

Those comfortable capable to entrust their BTC to a 3rd statement tin take nan services of manufacture first-movers specified arsenic Xapo Bank, which uses a bid of underground bunkers to safeguard their clients’ Bitcoin. 

The “Fort Knox” of Bitcoin 

“You’ve sewage different 5 minutes, past I request you to manus complete your phone,” said Albert Rocca, Xapo’s elder HQ relationship manager.

The erstwhile profession detective slipped our smartphones into an inconspicuous backpack arsenic our chopper chopped its measurement into nan Swiss mountains. The bag’s soul compartment is simply a Faraday cage, cutting disconnected our devices from immoderate connectivity and making our location untraceable. 

The chopper touched down astatine a mini landing portion nestled nether nan protector of a steeply ascending vista. At its guidelines is simply a smoothed-out granite aboveground pinch a azygous military-style bunker door. It’s nan first of galore hermetic vault doors barricading nan chartless mysteries inside. 

Entering this bunker involves an exhaustive information screening. After an ID cheque and pat-down, visitors are fixed a magnetic paper that they must usage to participate various points passim nan facility. 

The first awesome obstruction to introduction is nan six-ton vault doorway designed to withstand a atomic blast. The defender scanned his retina and entered a codification updated each infinitesimal earlier nan monolithic doorway gradually swung open.

The astir important vault doorway starring into nan installation weighs 6 tonnes. Source: Xapo Bank

Our group past moved into a smaller abstraction pinch different barrier. This time, a man-trap enclosure pinch bulletproof solid connected either broadside is utilized to measurement visitors’ weight and height. This biometric information is linked to nan magnetic paper identifying you arsenic you move done nan facility.

Finally, we entered nan bunker and were met pinch a passageway of exposed stone winding into nan upland for astir 30 meters, which led to nan adjacent group of information doors. This constituent requires entrants to execute a circumstantial activity to move through, which is different deterrent to bamboozle unwanted guests. 

The bunker is 1 of a fistful successful Switzerland that is dry, meaning that sections of its corridors are painted complete exposed rock. Source: Xapo Bank

Behind this doorway is simply a corridor pinch vault doors connected either side. Our entourage made its measurement to nan doorway that accesses Xapo Bank’s vault. 

Andrew Mannoukas, Xapo’s main accusation information officer, is 1 of a prime fewer who tin entree nan innermost room wrong nan vault. On this visit, his credentials were revoked truthful he wouldn’t beryllium taken hostage and forced to springiness america entry. 

A mini conception of nan bunker houses a number of infrastructure services secured by biometric scanners. Source: Xapo Bank

Behind nan last doorway is nan MPC shard, 1 of a number stored successful vaults astir nan world. It is required to motion transactions to negociate Xapo Bank’s BTC holdings. 

According to Mannoukas, nan sheer number of redundancies safeguarding nan infrastructure makes it astir intolerable for an attacker to return power of nan bank’s BTC.

“Why nan vaults? It’s each astir defense successful depth. The beingness information — those military-grade bunkers — adds different important furniture of protection. It guards against insider threats, earthy disasters and beingness theft attempts,” Mannoukas explained.

Xapo’s shards are distributed globally astatine undisclosed locations and held by different entities whose nonstop locations are chartless to each other.

This geographical dispersion is designed to guarantee that nary azygous individual, statement aliases entity tin entree each of nan shards, arsenic doing truthful would efficaciously assistance them power complete nan afloat backstage key.

A bunker prepared for everything 

Xapo Bank’s vault is 1 of galore services housed successful nan concealed bunker. The owner, whose personality is withheld to support nan site’s security, acquired nan installation successful a associated task pinch nan Swiss Air Force successful nan 1980s. 

Now independently owned, nan labyrinthine bunker houses each sorts of infrastructure, equipment and assets. 

The installation maintains each of its nuclear-resistant features. It houses 2 1-megawatt diesel generators and an intricate HEPA aerial filtration strategy that removes pollutants, including toxins and radioactive particles.

Two 1-megawatt diesel generators automatically startup successful nan arena of powerfulness failure, giving nan installation a powerful backup power source. Source: Xapo Bank

It besides uses an underground reservoir to cool server rooms and different utilities wrong nan bunker, eliminating nan request for power-intensive air-cooling systems. 

Different sections of nan bunker person higher information clearances. Access to a hidden emergency exit requires support from a distant information service. The passageway is equipped pinch a timer, and ambient greenish lights illuminate nan transition during nan allotted clip for crossing.

The bunker has galore hermetic doors breaking up introduction points to various sections of nan facility. Source: Xapo Bank

Another 6-ton doorway guards this entrance. The introduction constituent still features a military-era deterrent — a mini chute that allows a defender to driblet a grenade into nan corridor outside. The bunker is genuinely a surreal experience. It blends decades-old Swiss bunker building pinch cutting-edge exertion and infrastructure. 

Swapping multisig for MPC

Xapo Bank shifted distant from multisignature signing to protect its Bitcoin holdings successful 2023.

The institution has utilized these bunkers since its inception successful 2013, and nan multisig process progressive guards manually completing basking and acold wallet BTC movements daily. 

MPC exertion has made this redundant. Homomorphic encryption has wholly removed nan consequence of exposing backstage keys, adding an further level of information assurance. 

Related: European Central Bank is exploring blockchain and MPC technology

Mannoukas explained nan MPC signing process arsenic a group of chefs cooking a crockery together, pinch each cook having a concealed ingredient. 

The chefs adhd their ingredients to nan cookware without showing them to each other. They operation nan cookware together, pursuing a typical look that mixes everything perfectly. In nan end, everyone tastes nan last dish, enjoying nan mixed flavors, but nary 1 knows precisely what ingredients nan others added:

“This is akin to really MPC useful successful that each cook progressive (MPC shard) contributes their portion of nan signature without revealing it, and erstwhile combined, these shards create a valid signature that is capable to motion nan transaction.”

This way, nan group tin authorize nan transaction securely without immoderate azygous personification aliases entity holding nan complete backstage cardinal aliases nan backstage cardinal ever being assembled.

No disbursal has been spared successful delivering this level of security. The bunkers unsocial costs millions of dollars annually to use. 

The mixed information measures stay 1 of Xapo’s awesome drawcards. Its clients forego nan work of self-custody successful speech for exertion and infrastructure that astir modern banks don’t employ.

Disclaimer: Cointelegraph was personally invited to sojourn Xapo Bank’s vault, and nan institution covered its recreation and accommodation expenses.