RE: Apple crypto engineer position available

["Phillip Hallam-Baker" <hallam@ai.mit.edu>]

> Now, even though Apple had the help of RSA and BBN, there was this even
> bigger problem of just helping people get it. The best way to help people
> understand technology is to make it accessible so almost anyone can play
> with it and use it. This is what Apple is known for - making technology so
> accessible that people just go nuts, doing things with it and taking it
> places no one ever dreamed. That's how Apple catalyzed the transformation
> of the publishing industry. Requiring a CA to make DigiSign work simply
> made this impossible. A peer to peer model, allowing people to create and
> sign their own certificates would have been far more appropriate for
> Apple's creative users.  Then came PGP...

I think Mark makes a mistake in confusing pre-conditions for market
acceptance with requirements for market growth.

>From the perspective of someone who helped the Web grow from a userbase
of less than 100 users I have my own ideas as to why Apple did not
succeed with its powertalk architecture. I see the lack of commitment
to open standards as the key factor.

Consider the attractiveness of a communications system that only
communicates from one Mac to another. Today that might be just about
adequate for many people's needs, after all the PowerMacs are
quite powerful. Back in 1990 however the Mac platform was a rather
weedy 68000 with an operating system that was very expensive to
develop for and a relatively small market share.

If you had a power hungry application in 1990 you had to get a RISC
processor which in turn meant like it or not you had to use UNIX
(or VMS). Standardising on a Mac only platform just was not going
to happen regardless of how great the software was.


To the extent that requiring a CA meant higher startup costs the
powertalk architecture was flawed. The problem had always been a
chicken and egg situation in which PKI applications could not
take off without a CA and CAs could not take off without successful
PKI applications.

PGP cut the gordian knot and demonstrated that it was _possible_
to have a successful PKI application without a CA. But that is not
to say that a trusted third party cannot add value to an
application. PGP validated PKI generally but it did not invalidate
the CA concept - in the PGP system everyone is a trust provider,
everyone is in that sense a CA.


But just because CAs may be dispensed with in a system of 10,000
odd users whose principal concern is confidentiality does not mean
they have no role in a system of over 1 million users where the
legal enforceability of a signed contrat is an issue.

Consider as an example the case in which there are 1,000,000 users
and people generally prefer certificate chains to be no longer than
three people. That can only be achieved if either people on average
sign 100 keys or some people sign a great number of keys (thousands).
In my book anyone who is signing over 1000 keys had better have
a pretty decent idea of what they are doing and should probably
think of themselves as a CA.


The other shortcomming of Apple's approach was not realising
that there is a middle ground. To take an example most people
think of VeriSign as a CA because of our public CA business
(Server certificates, S/MIME certificates). A lot of people who
spend a lot of energy blasting our business model don't realise
that our enterprise offering, OnSite is a product which allows
other people to set up their own CA outsourcing the expensive
to implement Issuing Authority functions rather than handing
over control of their enterprise to us.

It is true that if folk want to issue certificates which are
incorporated into the VeriSign public hierarchy we insist on
certain contractual undertakings from them (i.e. if they issue
a certificate to Fred Bloggs they take the same steps we would
to check it really is Fred Bloggs).


We have already got to the point where we have proved the
viability of PKI generally. The question to ask is not what
are the preconditions for establishing PKI but how can we
grow the PKI market best?


In short Apple's plans were not too crazy from the perspective
of where they wanted to get. The fault lay in not understanding
how the market could get from where it is to where they thought
it should go. They failed to understand that communications
products can only be successful as genuinely open standards with
ubiquitous support. They saw the Powertalk architecture as a
means to sell more Macs, not as a business in itself.


		Phill