Prior art

Canton / Daml ledger model. Contracts with signatories, observers, controllers; the authorization rule (signatories authorize creation, actors authorize exercise, both jointly authorize consequences); projections and informees; consistency as create-before-use and no-use-after-consume; stakeholder-based confirmation. Everything in §4 is that model with participants replaced by proofs and the mediator replaced by J. The Polyglot Canton whitepaper's goal, sub-transaction privacy for EVM programs, is what this layer provides on an EVM settlement contract.

Zexe. Records with birth and death predicates and function privacy via a universal circuit. §4.7's witnessed method VK is the same idea with a registry instead of a universal predicate.

Aztec. Notes and nullifiers, private kernel recursion over a call stack, contract-class trees for VK lookup, in-circuit note encryption. K and J follow the kernel pattern; private calls (§12) would follow the call stack.

Bonsai. Uniform records and witness-selected branches for operation hiding, root windows, per-party anchored state. Applied here to whole transactions via fixed-shape fragments.

RFC-019 / RFC-020. The Cell and private-workflow drafts this layer refines (§10).