[Xastir] Is traffic encryption possible?

[Tapio Sokura]

On Fri, November 9, 2007 20:06, Jim Tolbert wrote:
> As the capabilities of Xastir are explored in our corner of the world,
> one query was raised in discussion.   Is there anyway, or more to the
> point, what would be required, to have GPS location packets encrypted?

It depends on what exactly you are trying to achieve. If you just want
secure transfer of APRS data over Internet to a private APRS-IS server,
you could use an encrypted tunnel without any changes to Xastir source
code. See stunnel.org for one example.

But if you want to encrypt the packets themselves, so they can be
transferred over unencrypted connections or maybe mixed with cleartext
packets, you need to get your hands dirty with Xastir source code. You'll
probably also want to keep your packets from never reaching the global
public APRS-IS. Anyway there is no such thing as an encrypted APRS
specification. So whatever system you use, it won't work together with
anything else, unless you modify the "anything else" part too.

> Similarly, what would be required to add another digit to the position
> accuracy that is transmitted and received?  Presumably, Xastir will plot
> whatever it gets as data.

Xastir supports APRS base-91 compression that provides a resolution of
under one meter globally. If I remember correctly, Xastir should also
support the !DAO! format that provides one additional minute decimal digit
to the basic resolution, yielding a resolution of at least 2 meters
globally. The basic position resolution of APRS is about 20 meters.

  Tapio