Design my protocol

[shamrock@netcom.com (Lucky Green)]

Here's a question for all the gurus out there: I work for a company that
manufactures a new concept in telephony hardware. The system we developed
essentially replaces PBXs with an off-the-shelf computer, some special
cards, and some software. Our system will offer all the features that you'd
expect from current PBXs, such as least cost routing, as well as other
features that can't be provided by a standard PBX.

When a customer sets up a site, the system connects via a modem to our
server, from which the system retrieves software, routing tables, etc. We
also offer periodic software updates, and software based add-on features
for an additional free. We would like to be able to upgrade, and in some
cases control, the sites by remote and we would like the customer to be
able to purchase extra software from us via modem or over the net. We use
TCP/IP and SNMP to comunicate with the sites. We want to include strong
crypto from the begining for several purposes:

-Link encryption between the customer sites and us.
-Authentication of the upgrade software.
-Secure purchases and transmision of software both via dial-up and the Internet.
-Optional encryption of the (telephony) data carried between sites.

I understand that the last issue is somewhat different from the others, I
just mentioned it to complete the picture. For now I need a solution for
the first two or three questions. We need something that can be delivered
to the customer six months from now, not something that may make it out of
a standard comittee years from now.

Thanks in advance,


-- Lucky Green <shamrock@netcom.com>
   PGP encrypted mail preferred.