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>I haven't thought about whether an actual blockchain is really the best solution... Most likely not. But the tech behind FBA (Federated Byzantine Agreement) d

by noxer 5y ago

>I haven't thought about whether an actual blockchain is really the best solution... Most likely not. But the tech behind FBA (Federated Byzantine Agreement) distributed ledgers would make an extremely reliable system that can handle malfunction of hardware and large outages of nodes. And since this is a write-only log and only some entities can write to it, it could be implemented with permission so that the system doesn't have to deal with attacks that public blockchain would face.

tialaramex 5y ago
Technically everyone can write to it. However you can only write certain specific things. In the case of Yeti 2022 you were only able to log (pre-)certificates signed by particular CAs trusted in the Web PKI, which were due to expire in the year 2022. In practice the vast majority of such logging is done by issuing CAs, as part of their normal operations. But it is possible (and is done purposefully, at least sometimes) to obtain certificates which have not been logged. These certificates, of course, won't work in Chrome or Safari because there's no proof they were logged. But you can log them yourself, and get SCTs and show those Just In Time™. This is only an interesting technical option if you have both the need to do it for some reason and the capability to send SCTs that aren't baked inside your certificates. The vast majority of punters just have the CA do all this for them and the certificate they get has SCTs baked right inside it so there's no technical changes for them at all, they needn't know CT exists. Because the CA's critical business processes depend on writing to logs, they need a formal service level agreement assuring them that some logs they use will accept their writes in a timely fashion and meet whatever criteria, but you as an individual don't need this, you don't care if the log you wanted to use says it's unavailable for 4 hours due to maintenance.
- noxer 5y ago
  Thats pretty much the default state of any blockchain like systems. You need a private key to write to it. Its just that in most public blockchains can have an infinite amount of new private keys can be generated an and some kind of token is attached to it. For a log none of that would be needed. A central operator could hand out keys to anyone who should be able to write to it and for all other its read-only. And ofc the key alone would still not allow someone to write invalid data.

by noxer 5y ago

tialaramex 5y ago

Technically everyone can write to it. However you can only write certain specific things. In the case of Yeti 2022 you were only able to log (pre-)certificates signed by particular CAs trusted in the Web PKI, which were due to expire in the year 2022. In practice the vast majority of such logging is done by issuing CAs, as part of their normal operations. But it is possible (and is done purposefully, at least sometimes) to obtain certificates which have not been logged. These certificates, of course, won't work in Chrome or Safari because there's no proof they were logged. But you can log them yourself, and get SCTs and show those Just In Time™. This is only an interesting technical option if you have both the need to do it for some reason and the capability to send SCTs that aren't baked inside your certificates. The vast majority of punters just have the CA do all this for them and the certificate they get has SCTs baked right inside it so there's no technical changes for them at all, they needn't know CT exists. Because the CA's critical business processes depend on writing to logs, they need a formal service level agreement assuring them that some logs they use will accept their writes in a timely fashion and meet whatever criteria, but you as an individual don't need this, you don't care if the log you wanted to use says it's unavailable for 4 hours due to maintenance.

noxer 5y ago
Thats pretty much the default state of any blockchain like systems. You need a private key to write to it. Its just that in most public blockchains can have an infinite amount of new private keys can be generated an and some kind of token is attached to it. For a log none of that would be needed. A central operator could hand out keys to anyone who should be able to write to it and for all other its read-only. And ofc the key alone would still not allow someone to write invalid data.