Based on the discussion, the draft now formally includes an additive ZK presentation extension while keeping the original fixed Groth16 interface intact.
Key updates:
- Introduced an additive interface (
IMultiTrustCredentialZKEx) for richer predicates. - Formally defined RANGE and DELTA (epoch-based) predicate semantics as OPTIONAL extensions.
- Clarified that the original fixed ABI remains the stable baseline (v1), preserving backward compatibility.
- Unified binding rules (anchor binding, address binding, comparison mask enforcement, and domain separation) across both the base and extended interfaces.
- Clarified
modesemantics as a bitmask (GT/LT/EQ), withmode == 0allowed only for KYC-only proofs.
Many thanks to allfinan for the thoughtful feedback and suggestions around range predicates, delta constraints, and epoch-based freshness.
The intent remains to keep MTC Core minimal, while allowing credit- and risk-oriented logic to evolve cleanly at the presentation layer.
Feedback on the extended predicate model and interface shape is very welcome.