"phil hunt" wrote in message
. ..
On Fri, 19 Dec 2003 13:43:49 -0500, Ray Drouillard
wrote:

Also, since it's not encrypted, it can be spoofed using a local
transmitter

That doesn't logically follow; it's possible to make non-encrypted
data that can't be faked, you just use a digital signature.

Is the European answer to GPS going to have digital signatures? If so,
how secure are they?

Any public-key encryption scheme I have seen uses large prime numbers.
They are secure because it's really difficult to factor the product of
two large prime numbers.

When the Europeans come out with their GPS system, and if it has some
kind of a digital signature, wanna make a bet about how long it takes
the US military to find a way to spoof it? It might be a long and
difficult computer search for the private key, or it might be something
as straightforward as using the intelligence community to ahem acquire
the codes.


Ray Drouillard