From: Mike van der Merwe <mikev@is.co.za>
Date: Wed, 14 Aug 1996 02:17:51 +0800
To: sasa.roskar@uni-lj.si
Subject: Re: PGP...
In-Reply-To: <009A6C9C.E823907E.18@uni-lj.si>
Message-ID: <3210771C.41C67EA6@is.co.za>
MIME-Version: 1.0
Content-Type: text/plain


Hi

>I'm confused.... if you don't want people to be able to read your
>email, you code it with PGP or other encoders... but why give away
>your key on your website to everyone? That makes your email readable
>to everyone... doesn't it? Oh well... I hope someone can explain this
>to me...

Not really, because when you generate a key, you generate a key, two are
actually generated: one public and one private. 

The public key you give to *everyone*, put in you signature, in the
newspapers and in your .plan; wherever. You also then have a matching
private key, which you NEVER give out.

Now the mathematics are pretty simple, but I'll pass over it.
Essentially your public key will decode what your private key encrypts
and your private key will decode what your public key encodes. 

So if someone uses your public key to send a message to you, only you
can decode it, since ONLY you have the matching private key.

This is used for signing as well. If you encrypt your message with your
private key, only your public key and decode it, since ONLY you have the
matching private key, if your public key, which everyone has, can decode
it, then ONLY you could have sent it. So to sign and encrypt a message
to someone all that happens is you encrypt your message with your
private key and then again with their public key. And it will be signed
(only you could have sent it) and encrypted (only they can read it)

I should mention at this point that pgp handles all this, because it
sounds very complex and time-consuming. To encrypt a message you simply
type:

pgp -e PrivateLetter.txt sasa.roskar@uni-lj.si

--> call pgp [pgp] and encrypt [-e] a message [PrivateLetter.txt] to the
recipient [sasa.roskar@uni-lj.si]. Pgp will look sasa.roskar@uni-lj.si
up in your own public keyring and use that public key. Signing is just a
matter of saying -s as well

Hope this helps, and is accurate.

Later
Mike

-- 
I'm sure we will find out in a few years that Microsoft invented the
Net.  Or brought it to the masses.  Or saved it from a certain and
early demise.  Or all of the above. 
     JAMES SEYMOUR