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On Thu, 26 Aug 2010 07:15:23 -0700, Darryl Ramm wrote:

Tim may have other concerns, but one problem is that secure flight
recorders use a private/public key signing mechanism (e.g. DSA). An open
source development project could not expose the private key. However I
don't see why this automatically makes this impossible in principle,
there could be schemes where a private key is held in escrow and not
disclosed even to the developers. The developers and hardware
manufactuer would also have to organize to have software releases IGC
approved.


Do you mean secure in the sense of not being able to tamper with a
signed, downloaded trace without it being easily detectable?

--
Alex

On Aug 26, 8:11*am, Alex Potter wrote:
On Thu, 26 Aug 2010 07:15:23 -0700, Darryl Ramm wrote:
Tim may have other concerns, but one problem is that secure flight
recorders use a private/public key signing mechanism (e.g. DSA). An open
source development project could not expose the private key. However I
don't see why this automatically makes this impossible in principle,
there could be schemes where a private key is held in escrow and not
disclosed even to the developers. The developers and hardware
manufactuer would also have to organize to have software releases IGC
approved.

Do you mean secure in the sense of not being able to tamper with a
signed, downloaded trace without it being easily detectable?

--
Alex

Yes. Anybody with the private key can sit at their computer make up an
entirely fake flight or edit an existing flight (e.g. take out a
restricted airspace incursion) and resign the IGC file and nobody
would be able to tell.

Darryl

Darryl

On Thu, 26 Aug 2010 08:25:25 -0700, Darryl Ramm wrote:

Yes. Anybody with the private key can sit at their computer make up an
entirely fake flight or edit an existing flight (e.g. take out a
restricted airspace incursion) and resign the IGC file and nobody would
be able to tell.


I don't think this runs as an argument. The downloaded file is, as far as
I understand it, signed by the "logger", rather than by the downloader's
computer, which makes checking for "fiddling" quite easy.

The developers can invent any key-pair they choose. The keys used in the
instrument will have been be hard-coded, therefore the private key is
already in the user's possession, even though hard, if not impossible(!?)
to read...

Potential cheats would need some considerable technical skill as well as
criminal(?) intent. Do such people fly gliders?

--
Alex