Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!gem.mps.ohio-state.edu!swrinde!ucsd!ames!sun-barr!newstop!texsun!texbell!attctc!sampson
From: sampson@attctc.Dallas.TX.US (Steve Sampson)
Newsgroups: sci.electronics
Subject: Re: Scrambling, encryption, etc. re:  phone privacy
Message-ID: <9813@attctc.Dallas.TX.US>
Date: 21 Oct 89 13:45:38 GMT
References: <1811@neoucom.UUCP>
Organization: The Unix(R) Connection, Dallas, Texas
Lines: 15


As an user of secure radios I must say your communication rate drops to
about 50% at fringe ranges.  With digital DS Wide-Band and the Narrow-Band
audio choppers.  Digital is the nicest to listen to, while the audio chopper
works with HF to UHF Narrow-Band radios.  In the fringe areas you lose sync
and the rest of the message is garbled or static (in wide-band).  Then you
say piss on it and go clear voice and break out the code book.  I'd say for
most police and investigators though, that secure voice can really be a
benefit to operations.  Currently you find them heading for a telephone to
communicate in private.  For home use the technology is here for simple
privacy schemes (lower than DES and NSA) that could be made affordable.
I'm playing with one scheme where I'm using two CODECS hooked to a Micro that
inserts between the headset and the phone.  In this case you can use any
algorithm you want.  I'm planning on using an XOR with a seeded random number
generator (the simplest).  Interesting subject.