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Diffstat (limited to 'docs/FOG-SX.md')
| -rw-r--r-- | docs/FOG-SX.md | 12 |
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diff --git a/docs/FOG-SX.md b/docs/FOG-SX.md index 336acae..67383ee 100644 --- a/docs/FOG-SX.md +++ b/docs/FOG-SX.md @@ -764,6 +764,18 @@ The high-assurance construction requires: - schematics, bill of materials, board photographs, continuity tests, optical direction tests, and teardown evidence for the exact hardware revision. +FOG does not assume that a PC provides a native TOSLINK port. The intended +high-assurance profile uses dedicated offline `TOTX` and online `TORX` boards +with narrowly allowlisted local interfaces. A consumer optical audio port or +adapter may support a functional experiment but does not establish physical +directionality. + +The optical diode constrains data flow through the selected fiber only. It +cannot stop a compromised offline Composer from placing plaintext, keys, or a +covert signal into the permitted offline-to-online output, and it cannot +protect unlocked Composer state from compromised local firmware, drivers, +peripherals, or host software. + TOSLINK defines optical transmitter and receiver device classes, not the complete FOG-SX modulation. Before activation the candidate must fix the exact NRZ or self-clocking line code, bitrate, transition density, preamble, clock |