More on PKI four-corner models

Extracts from internet-payments list 
(FSTC)

  "The four corner model is a valid business 
model with all four parties
   filling a valid business role .... 
totally independent of whether the
   delivery vehicle involves 
offline, stale, static certificates."

 

On the contrary.   If the TTP (credential 
issuer) is a part of a trust-network, the fourth 
corner (acquirer) is redundant as there is 
nothing a fourth party can add but costs[1].  That is, if we talk 
about authentication, and not about the 
transferal of money.

 

1] Including:

- Subscription fees

- Transaction fees

- Proprietary trust network software

- Relying party credential issuance and 
configuration

- Trust network arbitration software

 

I claim that the Four Corner model is the single 
most hampering thing to wide-scale PKI-deployment 
because it makes receivers' possibly pay for 
messages that they maybe did not even wanted!

 

In  paper-based messaging (excluding all kinds 
of payment systems), the "sender" 
typically puts on a stamp on a letter to get it distributed.  This makes sense, four-corner does not.

 

May I end this letter citing an interview with Bill 
Gates?

 

Q: In 1995, you wrote in your book, "The Road 
Ahead," that IT will realize friction-free capitalism by excluding middlemen 
and directly connecting buyers and sellers. Do you still believe in the 
idea?

A: Oh absolutely. I believe there should be no markup in any area 
of the B2B marketplace. If you want to buy and sell from anyone in the world, 
you should just get very inexpensive software. They'll let you see 
every seller and let you do complex transactions without anybody marking up 
the cost of what you're buying. XML Web services are needed for that, and 
that's what we're doing. It's a key building block of friction-free 
capitalism.

 

Anders Rundgren

Consultant, PKI and e-infrastructure