Re: The RF-5151DE digital encryption option

[koontzd@lrcs.loral.com (David Koontz )]

From the size of the key space, it sounds like a big shift register and
preset.  While Harris has manufactured shift register based secure voice
specified by NSA, it doesn't sound like it is military.  As a guess it
would be intended for export to friendly nations.  A lot of military
radios have board slots for a COMSEC board with whats called a trigraph
designator (E-ABC).  While I don't recall the actual trigraph designator,
it shows us in recent advertisements.  At least one foreign radio 
manufacturer (Israeli) also provides their own encryption module for
sale to friendly nations.  It used to be popular to supply DES.

Quite a few corporations offer their own encryption algorithms.  AT&T
offers at least two, one of which is exportable.   They advertise a
112 bit key, I think.