lauren@vortex.UUCP (Lauren Weinstein) (11/11/84)
While I haven't worked out all of the details, I can see one reasonably
practical method for fairly "secure" communications (for login
sessions with a central computer) via ham packet radio.
This technique assumes either a specialized hardware device, or
a programmable terminal (e.g. Radio Shack Model 100 or some such)
on the remote end. The technique would involve synchronizing a long
pseudo-random sequence on both the mainframe and remote ends, and then
including the "next" element of the sequence as "non-information"
data in each packet sent to the mainframe. This sequence might be
as small as one word or byte of sequence info per packet, and would be
inserted by the remote terminal device--it would not require modifications
to the packet radio boards. While maintaining synchronization would
not be trivial, it should not be terribly difficult.
Additional security might be provided over login sequences, including
specialized pseudo-random query/response sequences to replace
conventional logins via the packet radio channel.
This sort of technique would provide a high level of integrity and
control over sessions, yet would not require the (presumably illegal)
use of encryption over full sessions. It would have the ability
of providing sessions which would ONLY respond to packets from
the designated user and would ignore all other transmissions.
I welcome comments on this technique.
--Lauren--
{decvax, ihnp4, allegra, seismo, clyde}!vortex!lauren