You miss the point entirely.

There is no signature on the GPS signals, therefore any system capable of
generating GPS signals can feed them to a flight recorder via the antenna,
exactly like the real satellite system. All the flight recorder can do is
take the data, and generate a signature proving that what *it received* has
not been tampered with.

Pseudolites ( GPS generators for test purposes ) are available, at least 5
manufacturers, by my very cursory search a while ago. They are still
relatively expensive, but not much in comparison to the cost of setting up
to do a world record.

Fooling the pressure transducer and engine noise detection systems on the
average flight recorder is a relatively trivial matter, for those who want
to cheat.

--
Regards,

Adrian Jansen
J & K MicroSystems
Microcomputer solutions for industrial control
"Robert Ehrlich" wrote in message
...
Paul Repacholi wrote:
...
If anyone is going to fabricate records, then just feed the whole
system from a pseudolite set. No need to get inside the systems at
all.
...

This is just what the cryptograhic RSA signature makes impossible,
not to fake such records, but to put them in an IGC file that the
validation program accepts as a genuine file coming from the logger.