Nothing to hold TS to account

[JAG-UK]

Would be good to have an API that allows checking or proving consistency of the log.
We understand that not every log supports consistency proofs but in the cases where they do, there should be standard way to get them

[achamayou]

Discussed with @SteveLasker and @OR13, the most useful step in that direction would be to specify a stand-alone consistency proof format, at which point it would make sense to have an API allowing a client to request a consistency proof from a point to another point in a ledger history.

[robinbryce]

@achamayou / @JAG-UK would an api which responded with the VDS appropriate proof type work ? https://github.com/cose-wg/draft-ietf-cose-merkle-tree-proofs sais "COSE Receipts" but it actually allows a VDS to define any proof format that it deems relevant.

Two tricky aspects I see:

1. The requested proof, consistency in this case, may be "not ready yet". Its not as clear how to deal with that as for proofs of inclusion.
2. Depending on the VDS (transparency service choice) different parameters may be required for the request. That suggests the API itself needs to allow for VDS specific parameterization

[achamayou]

@achamayou / @JAG-UK would an api which responded with the VDS appropriate proof type work ?

I think it would?

1. The requested proof, consistency in this case, may be "not ready yet". Its not as clear how to deal with that as for proofs of inclusion.

That sounds similar to the situation for proofs of inclusion, which may also be behind an async API because the ledger needs to do something that takes a bit of time first (replicate across N nodes etc).

2. Depending on the VDS (transparency service choice) different parameters may be required for the request. That suggests the API itself needs to allow for VDS specific parameterization

Yes, that seems like the main obstacle to me. I don't know if this could be resolved by defining an (ordered, but opaque) transaction ID, and if from and to would be enough here, or if more is needed.