From: felix@hu.se (Felix Ungman)
Date: Fri, 5 Nov 93 02:32:28 PST
To: jdblair@nextsrv.cas.muohio.EDU
Subject: Re: Macintosh PGP CDEV Idea
Message-ID: <199311051029.AA15275@mail.swip.net>
MIME-Version: 1.0
Content-Type: text/plain


I have some ideas I've been working on (a modular approach). To be
sucessfull, a cryptographic utility for the Mac has to fit nicely into the
system.

Here's my proposal (divided into five layers):

1 - CryptoModules
To do encryption we need cryptographic algorithms. These are written as
small modules (code resources) and are put into the Extensions folder. They
contain algorithms but no user interaction. 
It's easy for the user to install and upgrade CryptoModules. It's also easy
to write new modules, as you don't need to worry about user interfacing,
and can concentrate on the algorithms.

2 - CryptoAccess
This module is the interface to the CryptoModules. It provides c/pascal
routine interface and scripting abilities (AppleEvents). Contains no user
interaction, and is key oriented (it looks up the right algorithm for a
given key).

3 - CryptoAPI
This module handles the user interaction. Provides the dialogs and menus
neccesarry for encrypting/signing data. Accessed by c/pascal routines or
AppleEvents.

4 - Applications/Utilities
With the CryptoAPI it's easy to write encryption capable programs. Very
little code has to be added to existing applications. A nice utility would
be encryption of text in TextEdit.

5 - Integration with System 7 Pro
Patching the Digital Signature Manager will extend the system in a
consistent way. All neat features (like signing in the Finder, etc) will
also work with PGP.

Unfortunately, I haven't enough spare time to do all this myself. The layer
model makes it possible to divide the work that has to be done.

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True Name: Felix Ungman               "Gen is god and your God is not"