Coinbase reveals how it once guarded cold storage keys with Faraday cages

Coinbase once generated the keys to its cold storage inside Faraday-caged tents, set up at secret locations around San Francisco. Inside the key ceremony Start with the Faraday cage. Think of it as a mesh enclosure that stops electromagnetic signals from getting in or out. Electronics leak faint signals while they run. In theory, a well-equipped attacker could capture those emissions and reconstruct sensitive data. Security researchers call these electromagnetic side-channel attacks. Coinbase’s answer was to wrap the whole key generation process in a shield. The keys were created inside Faraday-caged tents, so whatever the machines emitted stayed inside the tent. The tents also moved. Coinbase erected them at unpredictable locations in San Francisco, which made it much harder for anyone to plan surveillance ahead of time. The hardware got the same treatment. Coinbase used two factory-sealed laptops for the job, one for generating keys and one for printing. One ran Linux. The other was a MacBook. Both machines were air-gapped, meaning they never touched a network. Then came the coin toss. The laptops were chosen by flipping a coin. If nobody knows in advance which machine will be us...