From: thug@phantom.com (Murdering Thug)
Date: Mon, 9 Aug 93 18:16:41 PDT
To: perobich@ingr.com
Subject: re: Secure voice software issues
Message-ID: <m0oPiMJ-0009GJC@mindvox.phantom.com>
MIME-Version: 1.0
Content-Type: text


Paul,

I noticed you mentioned that you will be using key rings in your
cryptophones, so here's an idea I think would be great for cryptophones. 
This is a simple solution to the key-exchange problem.  Cryptophone users
would not need to exchange keys beforehand nor need to store other
people's public keys on their cryptophone. 

- Every cryptophone user has a public and private key pair (like in RSA or
  PGP)

- When a person calls another person, the phones automatically exchange their
  public keys before the voice conversation begins.  Obviously the private
  keys are never transmitted.

With this method, all one needs to initiate a secure telephone
conversation is the phone number of whoever you're calling, just like
using a regular telephone.  I am assuming this is how Clipper/Skipjack
phones would do this.  I hope your cryptophone software does this as well,
since I don't want to or need to keep keyrings full of public keys of
everyone I might ever have to call.


Thug