> > nodes on your home network when one talks to another. That > would be a bit > > hard to manage: a certificate for each of your machines at > home, possibly > > including home appliances which are on the network. > > Why is a certificate-per-machine hard to manage? It has been made hard because people have been insisting on applying PKI techniques designed to support authentication of humans to authenticate devices. With a device you can embed a private key during manufacture that is unique to the device. We already do this with cable modems (and no the economics are not prohibitive). I just published a White paper on this subject on the VRSN research web site: http://www.verisignlabs.com/Papers/ACC1.html The basic idea is to embed a private key in the device during manufacture, tie the public key to the serial number of the device using a certificate and use the combination for the SOLE PURPOSE of authenticating the device when it applies to authenticate application keys that are generated in the device during initialization. If the device is decomissioned the applications keys are cleared but the ACC key remains so that the next purchaser can initialize it. The genuinely paranoid (i.e. the military) might have the option of paying a lot more to install their own ACC keys The objective is plug and play for cryptography. Every device should initialize with the absolute minimum of fuss. This needs to be simple enough that your granny can install it. This does not remove the need for certs to authenticate humans. But that is a separate layer of authentication. Phill
Phillip Hallam-Baker (E-mail).vcf