From: cscon0151@uoft02.utoledo.edu
Newsgroups: alt.radio.scanner
Subject: Re: 800MHz Trunked Radio System Signals
Date: 30 Dec 92 17:11:19 GMT
Organization: University of Toledo, Computer Services

mikebo@timesink.chi.il.us (Michael Borowiec) writes:
>john@anasazi.com writes:
>>Keywords: 
>>
>>In article <92360.134725PJB113@psuvm.psu.edu> me <PJB113@psuvm.psu.edu> writes:
>>]As more and more services switch to trunked systems, I'm sure the scanner
>>]companies will eventually develop scanners with trunking capabillities. I
>>]strongly believe that the same thing is true with digital encryption. Too
>>]much money is involved in communications monitoring for it to go down
>>]the tubes just because of trunking and encryption. -PJB
>>
>>A couple of problems with this:
>>  (1) It seems like each trunking system uses different signalling technology.
>>      Thus any scanner would have to be able to handle a bunch of these,
>>      and would become obsolete quickly. 
> 
> Agreed...
> 
>>  (2) It is illegal to receive digitally encrypted signals. I don't know
>>      if it is illegal to build decryptors, but if it isn't, it would be
>>      quickly.
> 
> I don't think you can outlaw a thing... only the illegal use of a thing.
> There are exceptions however, such as drugs and dangerous weapons. I don't
> think an electronics hobby kit would fall into this catagory. That's how
> companies get away with selling cable de-scramblers - in kit form.
> 
>>  (3) The digital encryption schemes are quite strong. I doubt that you
>>      could afford a scanner that could decrypt them (without knowing the
>>      key beforehand). Such a scanner would probably cost at least
>>      $20,000,000 (in order to crack the DES code). Now, you are probably
>>      going to respond "yeah, but they cracked the Videocipher" to which
>>      I shall pre-emptively respond: "Yes, but that's different."
> 
> I dunno about the $20M part. (-8  Now you can buy a 50MIPS machine
> under $5000. Within a year or two, you'll be able to buy a 100MIPS
> machine for the same $. The DES code is only RELATIVELY secure. Just
> read anything on the NSA if you doubt that. They eat DES encoded
> messages for lunch. The US Government wants to establish the DES as
> a standard so they can read your mail while still permitting you
> RELATIVE protection from your competitors. Note that vendors sell
> two different types of DVP equipment: one for businesses/consumers
> the other for government use.
> - Mike
> 
> --------------------------------------------------------------------------
> Michael Borowiec  (N9EUZ)  -  mikebo@timesink.chi.il.us  -  mikebo@isc.com
>   >>> Dedicated to the Pursuit of Computer Assisted Time Dissipation <<<
> --------------------------------------------------------------------------

I've heard the designers of DES made the code too difficult.  The NSA, which
apparently has to approve the encryption format,  thought that code was too
difficult, and purposely flawed the encryption standard.  That's what the
people in sci.crypt told me (I think it was them).  Anyways, the sci.crypt
newsgroup has some good info about DES and DVP,  at least they did a couple
months ago.

Later...

Brad Steinman
University of Toledo Computer Services
cscon0151@uoft02.utoledo.edu
Newsgroups: alt.radio.scanner