Physical Isolation: The Air-Gap is Not Enough
For elite institutions, security must move beyond the digital. If an attacker can see the electromagnetic radiation from your laptop, they can see your private keys.
TEMPEST Protection
TEMPEST is a NSA specification for preventing eavesdropping through emanations (EMI/RFI).
- EMI Shielding: Using shielded cables and cages to block signals from leaving the signing room.
- Acoustic Jamming: Using white noise to prevent laser-microphone eavesdropping on keyboard clicks (which can be used to reconstruct passwords).
The Institutional "Safe Room"
A dedicated, windowless room with 100% Faraday shielding where all high-value transactions are signed.
📋 Security Checklist: Signing Room Audit
- No Mobile Devices: All phones left in biometric lockers outside the perimeter.
- Isolated Power: Does the signing room use a dedicated UPS to prevent power-line side-channel attacks?
- Visual Privacy: Are there 0 cameras or glass windows with a line-of-sight to any screens?