Subject: Re:need help from the ietf list...PKI

From: Doug Royer <[email-masked]>
Date: Sun, 21 Dec 2003 15:25:20 -0700

I agree. With my mortgage customers (MISMO.org related) I have
argued that private certs signed by their business partner is better than a
cert issued by a well known cert company. Anyone can buy a cert from
the well known company.  A cert signed by your business partner
can not be bought from any vendor. And if managed correctly
they can add/delete employees and application certs real time.

>
> However, PKI does not help e-commerce or financial transactions,
> as discussed in my recent paper: "Meaninglessness of Public
> Key Cryptography for Authentication on Consumable Credential"
> (presented in Japan in Japanese):
>
>     Abstract: For electric transactions, the essential benefit
>     of public key cryptography over shared key cryptography is
>     that it is not necessary to communicate with Certificate
>     Authority on each transaction. However, it is meaningless
>     to use public key cryptography for authentication on
>     consumable credentials, such as authentication of remaining
>     credential in account for electric payment, as fraud with
>     tremendous damage is easily performed, unless communication
>     with authorities to manage the account decrease remaining
>     credential is required on each transaction.
>
> The problem of PKI without realtime management of remaining
> credential is that an attacker can use 1K USD worth of certs
> from 1000 different locations for 1000 seconds 1000 times a
> second, total amount of damage of which is 1T USD.
>
> Credential can be created only with direct communication.
>
>                         Masataka Ohta
>
>

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From: Masataka Ohta <[email-masked]>
Date: Mon, 22 Dec 2003 14:08:22 +0900

Doug Royer;

> the well known company.

As long as the cert company is a bank, you deposite money to the
bank, the bank issues a cert for the amount of the money and your
bank account is checked and reduced at the time the cert is used,
there is no problem to use the bank as a well known cert company.

A problem is that there is no reason to use PK, then.

> And if managed correctly

As it is realtime, we don't need complex features of PKI. We,
for example, don't need timestamps in certs nor CRLs.

> A cert signed by your business partner
> can not be bought from any vendor.

Still, with established interbank trust relationships, you and
your business partner can send and receive money through your
and partner's banks.

Execpt that you can use cryptographic security (most likely
shared secret ones), it is no different from the current
business style to use banks to send and receive money.

						Masataka Ohta

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From: Doug Royer <[email-masked]>
Date: Mon, 22 Dec 2003 11:05:22 -0700

Masataka Ohta wrote:

> As long as the cert company is a bank, you deposit money to the

The usage is not for money transfer, it is for document transfer.
So long term certs with CRL's is still needed.

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