Russ Crynwr writes:
> Hey, I went into the local New York State Police station and asked if
> they had email. The answer is basically "No." They've got something
> like a telex system. I doubt that they're any encryption on their
> data services. You'd think that police department RADIOS would at
> least be encrypted! Thanks, TLAs, for your crime encouraging efforts.
> [ TLA lurkers should have the grace to wince at that. ]
Actually there is quite a strong school of thought that holds
that police should be discouraged from using hard encryption on their
radios because that makes it impossible for the media and public to keep
an eye on them to make sure that they are on the up and up. Remember
that policeman carry guns and have wide discression in what they can do
in many situations, especially in short term immediate situations. And
quite a few are not well educated or terribly bright. And most members
of the general public are inclined to believe the word of police rather
than some random citizen.
A hard encrypted police radio system restricts public
information about police activities largely to what the police chooses
to voluntarily reveal to the media - and given the self promoting
political games, corruption, fabrication of evidence, brutality, racism
and plain stupidity that characterize all too many police departments
that often is not enough and very very self serving. Leaving police
radio communications at least mostly open allows the media and curious
citizens to follow and observe police actions and have enough knowlage
of what went on to ask the hard questions and be witnesses to the
actual events.
Many police radio systems have been deliberately left open in
recent years even as digital DES based technology has become practical and
somewhat affordable and widely installed. Lots of police departments
have agreed or been forced to not encrypt anything but sensitive
undercover surveillance related coms, and certain tactical coms in
crisis situations such as hostage takings. (It still remains also true,
however, that digital voice radios systems have less range, penetrating
power and more unpredictable outages and dead spots than good old analog
fm systems do so there is an added benefit to not using encryption).
And most police officers seem to believe that allowing the
public to listen to their communications is a net plus - there are
apparently few known instances of criminals making particularly
effective use of scanners to thwart the police and lots of instances of
citizens spotting suspects and other suspicious activities and informing
the police because they knew they were interested from what they
overheard listening to a scanner.
As for police digital communications (the so called MDT
terminals installed in many police cruisers) - the older and larger city
systems installed mostly by big companies such as Motorola use feeble or
non existant encryption and can be readily intercepted by a slightly
modified scanner (using radio shack parts) and a PC with suitable
software (though the baud rates are odd, the data format synchronous
rather than start-stop async, the messages mostly sent in the form of
packed codewords in some BCH or Reed Soloman error correcting code with
the data bits strangely distributed in the codeword for best error
immunity, and the actual data a hodgepodge mixture of ASCII text and
binary screen formating and control characters).
The MDT systems installed in smaller towns and more recently by
a small company founded by a former colleague of mine (K1EA) that use
standard laptops instead of proprietary terminals do use single DES
encryption (my pro-crypto rantings on slow afternoons many years ago may
have had some effect). I don't know how good the key management is - I
keep meaning to ask Ken the next time I see him at a hamfest - but at
least the data is not sitting there for the taking by anyone with a PC,
a scanner, and some reasonably straightforward DOS software.
I have been told that interconnecting non secure digital terminal
systems with the various federal and state criminal data base systems
such as NCIC and its successors that contain sensitive non public information
such as criminal histories and arrest records is supposed to be illegal.
It is not clear how completely this rule is observed.
Crypto in the real world raises some interesting issues - the
nazis or fascists in the evil sense in the future will certainly make
very effective use of it to do evil.
Dave Emery
[email protected]