Nonsense. One can simply cache the certificate, exactly as one does with SSH. In fact, Mozilla at least does exactly this if you tell it to. The reason that this is uncommon is because the environments where HTTPS is used are generally spontaneous and therefore certificate caching is less useful.
there are actually two scenarios .... one is to pre-cache it (so that its transmission never actually has to happen) and the other is to compress it to zero bytes. detailed discussion of certificate pre-caching and certificate zero byte compression:
http://www.garlic.com/~lynn/ansiepay.htm#aadsnwi2
the typical use for HTTPS for e-commerce is to hide the account number on its way to the financial institution. for the most part the merchant is primarily interested in the response from the consumer's financial institution on whether or not the merchant gets paid. If it weren't for the associated business processes, the merchant could get by with never knowing anything at all about the consumer (the merchant just passes the account number on ... and gets back what they are really interested in .... the notification from the bank that they will get paid).
So a HTTPS type solution is that the consumer pre-caches their bank's certificate (when they establish a bank account). .... and they transmit the account number "hidden" using the bank's public key. This happens to pass thru the merchants processing .... but for purposes of the authorization, the merchant never really has to see it. The protocol would require minor issues of replay attacks .... and be able to be done in a single round trip .... w/o all the SSL protocol chatter. Actually, is isn't so much pre-caching their bank's certificate .... as loading their bank's public key into a table .... analogous to the way CA public keys are loading into tables (aka using out-of-band processing .... the convention that they may be self-signed and encoded in a certificate format is an anomoly of available software and in no way implies a PKI). The primary purpose of HTTPS hasn't been to have a secure channel with the merchant, the primary purpose of the HTTPS is to try and hide the consumer's account number as it makes its way to the consumer's financial institution.
The other solution is the X9.59 standard (preserve the integrity of the financial infrastructure for all electronic retail payments, not just internet, not just POS, not just credit, ALL; credit, debit, stored value, etc) that creates authenticated transactions and account numbers that can only be used in authenticated transaction. The consumer's public key is registered in their bank account (out of band process, again no PKI). X9.59 transactions are signed and transmitted. Since the account number can only be used in authenticated transactions .... it changes from needing encryption to hide the value as part of a shared-secret paradigm to purely a paradigm that supports integrity and authentication. As in the above, scenario, the merchant passes the value thru on its way to the consumer's financial institution; and is focused on getting the approved/disapproved answer back about whether they will be paid. As in the bank HTTPS scenario where the bank's pubilc key is pre-cached at the consumer, the pre-caching of the consumer's public key is pre-cached at the bank .... involves no PKI business processes (although their may be some similarities that the transport of the public key involves encoding in a certificate defined format). misc. x9.59 refs:
http://www.garlic.com/~lynn/index.html#x959
Both pre-caching solutions are between the business entities that are directly involved; the consumer and the consumer's financial institution based on having an established business relationship.
The invention of PKI was primarily to address the issue of an event between two parties that had no prior business relationship and possibly weren't going to have any future business relationship and that they would conclude their business relying on some mutual trust in the integrity of a 3rd party w/o actually having to resort to an online environment. The e-commerce scenario is that there is real-time, online transaction with the trusted 3rd party (the consumer's financial institution) involving prior business relationship. This negates the basic original assumptions about the environment that PKIs are targeted at addressing.
--
Anne & Lynn Wheeler http://www.garlic.com/~lynn/
Internet trivia 20th anv http://www.garlic.com/~lynn/rfcietff.htm
---------------------------------------------------------------------
The Cryptography Mailing List
Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED]
