[TMRA] Data modes and encryption

[Leif Burrow]

Section 97.113 - *Prohibited Transmissions**(a) No amateur station shall
transmit: ... (4) ... messages in codes or ciphers intended to obscure the
meaning thereof ...

*Uuencode is neither encryption nor meant to obscure the meaning of your
transmission so I would think it would technically be ok. It's just a well
known encoding standard for files much as cw is an encoding standard for
text.

It is however better known in computer circles than radio circles.  If I
were doing this I would be sure to send an explanation of what it was along
with the url of a place one could download uudecode before and after. Even
then I wouldn't be too surprised if someone got the wrong idea and took it
for encryption, that or junk text sent to jam someone.  It also might be a
long transmission. I would steer well clear of occupied frequencies. Watch
the 10 minute mark too.

This could be an interesting thing to try as PSK uses less bandwidth and
gets far more range per watt than the FM or SSB which are normally used to
send SSTV.  I would think trying this would be well within the spirit of ham
radio.  Isn't it supposed to be about experimenting with technology?

PGP is probably out.  I have wondered myself if one could sign something
with their private key while sending the public key out plain text.  If
someone did I would assume they would send the public key out every time at
the beginning and/or end of transmission.

For those not familiar with PGP, or with public/private keys here's how they
work.  You have two 'keys'. If you use one to encode a message the other
will decode it.  You keep one to yourself, this is your private key.  The
other you give away to anyone who wants it.  In this case one would probably
just send it along with the transmission. Now, when you encode a message
using your private key your original message isn't really obscured from
anyone because they have the public key too.  Anybody can decode your
message using the public key.  The trick is this.  If someone uses your
public key to try to decode a message that was encoded using someone else's
private key then all they get is garbage.  It only works to decode messages
encoded with your private key.  If you kept the private key secret then your
public key only works on messages encoded by you.  This proves that the
message was sent by you.

If nothing else this would prevent non-licensed people from pretending to be
hams. (Or hams pretending to be one another).  It would be nice for things
like repeater control, r/c stuff and and the like. I think this is
definitely within the letter of the law as it does nothing to obscure the
meaning of your transmission but it is probably going too far. From what
I've seen in discussion on various forums I don't think the majority of hams
would interpret things this way and if they started reporting you I'm pretty
sure the FCC would just go with the consensus. I would not do the
public/private key thing yet, I'm only mentioning it to see what discussion
it gets going.

These are just my thoughts.  I am not a lawyer, just a ham who has read part
97. I claim no responsibility if something I wrote causes you to be fined,
go to jail, your wife to leave you, your dog to run away or you to lose your
license.

Leif Burrow
KC8RWR



On Sun, May 9, 2010 at 11:26 AM, <KB8NXO at access-ohio.net> wrote:

> Is base64 and other methods of sending files considered encrypted when
> using
> PSK31? Is it illegal? From what I have read so far PSK31 works with text
> but
> not images. I believe images and other files could be sent with
> Base64/uuencode/uudecode. And it could also send pgp/gpg encrypted files.
> There are many possibilities.
>
> Can it be done with the FCC's blessing????
>
> Rick
> KB8NXO
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