Operation of a NIAP PP4.0 secure isolator

Isolators are hardware devices designed to ensure an unidirectional separation between a computer and its peripherals (monitor, keyboard, mouse).

They prevent any information leakage, even in the event of a software or physical attack.

They ensure:

• A strictly unidirectional video flow: computer → monitor
• A strictly unidirectional keyboard/mouse flow: peripherals → computer
• No opposing flow is possible, even if the equipment is compromised.

General architecture of a NIAP PP4.0 secure isolator

The architecture of the isolator is based on a complete physical separation between the computer and its peripherals. A dedicated system controller drives the whole system, loads firmware into non-modifiable memory, and performs self-tests at startup to ensure the integrity of the device.

Keyboard and mouse signals pass through USB emulators that verify the peripherals are authorized, then are transmitted through optical diodes, creating a strictly unidirectional flow to the computer, with no possibility of return or reverse manipulation.

The video path is designed on the same principle: the signal goes from the PC to the monitor only, while a Emulated EDID completely protects the display configuration channel by blocking any attempt to write or exploit it by the computer.

Finally, the whole is protected in a tamper-proof chassis welded, accompanied by holographic seals that allow detection of any unauthorized opening attempts.