2) The transmitted data would be sent encrypted and only the ciphertext would be recorded by the ground stations. Encryption would be done using symmetric ciphers. The encryption key would be set before every flight by a NTSB technician, and known only by the NTSB (or the equivalent agency if the flight originates overseas).
With the greatest of respect at this time, I still wish that US posters would consider the outside world. I find it difficult to believe, genuinely, that after what happened last week, people still have the mindset that US-based agencies somehow have worldwide authority and access. The NTSB is a US agency, and any scheme like this - which in my mind has great merit - would need the oversite of an international agency to work. Peter