Nomen Nescio <[EMAIL PROTECTED]> writes: >If a key is misused, i.e. "scraped" out of the TPM and used to create a >virtualized, rule-breaking software TPM, it can be revoked. This means that >all the TPMs that share that one key lose the use of that key. But it doesn't >matter much, because they each have many more they can use. Since it is >expected that only a small percentage of TPMs will ever need their keys >revoked, most TPMs should always have plenty of keys to use.
I designed something along these lines some years ago as a way of building a fault-tolerant key management system. The idea is that you create a pile of keys, and these vote on key updates. If a key is compromised, you sign its replacement with a quorum of non-compromised keys, and replace the bad key. You also periodically roll over keys as a preventive measure, limiting exposure due to compromises. No need for a PKI or anything else complex like that, it's all automatic and transparent. There can be slight problems if a device stays offline long enough that enough keys have been rolled over to make reaching a quorum impossible, which was an issue when I designed the thing but rather unlikely now. I can dig up the exact details in case anyone's interested. Peter.