Beat me to it! ;^D

I was going to suggest a similar system where the transponder holds the key pair, encrypts a block of information including the ship's ID, registered name, any other relevant information and the current date and time. It then broadcasts the public key and the encrypted data. The transponder would automatically synchronise its clock with the master clock at any star port when you docked there  (and a simple addition to the standard information block would be when and where that had last been done).

You can record the signal if you want, but any recipient would be immediately aware that it was an out-of-date one and therefore suspect.


On Tue, 2 Apr 2019 17:38 Catherine Berry, <xxxxxx@gmail.com> wrote:

It would be pretty easy to design a hard-to-spoof system using public key cryptography. Each ship and traffic control system broadcasts its public key. Signals in either direction are encrypted using the public key, and decrypted using the private key. Combine that with a wide distribution system for known public keys (presumably as part of the shipping registry) and it's trivial to authenticate that anyone is either (a) who they say they are, or (b) obtained the private key of the entity they're pretending to be. Grabbing private keys and outrunning their invalidation update message might be a good motive for piracy or espionage.

Note that this removes the need for a sealed black-box transponder. Everything can be open and accessible. The private key and the subsystem that handles encryption/decryption are the only things that need to be carefully protected.

On Tue, Apr 2, 2019 at 6:14 AM Bill Rutherford <xxxxxx@comcast.net> wrote:

All,

In canon, can a ship record another ship's transponder broadcast, and

rebroadcast it, essentially taking over that ship's identity?

I've found very little online and the only printed reference that

discusses it much at all is the Starship Operator's Manual Vol 1,

published by Digest Group back in 1988.  Their "short version" is

that the transponder is in an essentially unbreakable black box that

requires a licensed technician to reprogram (i.e. change the signal

being sent).

One of my players is intent on sending a bogus transponder signal but

doesn't want to go so far as altering the black box.  His plan is

"harvest" a transponder signal sent by a random ship after turning

off his own ship's black box.

So - back to my original question, would this work?

One obstacle I can think of would be if the transponder sends some

sort of authentication code based on a "seed" of some sort (kind of

like the way a Symantec cybertoken uses a random number seed only

elsewhere held on a Symantec server somewhere) which would be more

difficult than most would be willing to deal with - to duplicate.

What other obstacles, other than saying "That's now how they

work!  You cannot rebroadcast somebody else's transponder signal

because the Imperium, in their wisdom, incorporated handwavium into

the transponder that precludes this sort of thing" might there be?

In advance, thanks!

Bill Rutherford

xxxxxx@comcast.net

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