# Zero-Knowledge Policy Attestation

**Meta-Universe Specification**

**Document ID:** MU-V2-FED-014  
**Title:** Zero-Knowledge Policy Attestation  
**Document Class:** Informative  
**Version:** 2.0 (Draft)  
**Status:** Working Draft  
**Normative References:** None  
**Informative References:** [Security-Model](../03-federation/Security-Model.md), [Trust-Model](../03-federation/Trust-Model.md), [Decentralized-Registry](../06-ecosystem/Decentralized-Registry.md), [MMAS-Interchange](../02-architecture/MMAS-Interchange.md), [Consent-and-Disclosure](../03-federation/Consent-and-Disclosure.md)  
**Copyright:** © Orkestron.AI  
**License:** Apache-2.0

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# 1. Purpose

When AI agents of *different organizations* federate, each side wants assurance
that the other obeys agreed security and compliance policies — but neither wants
to reveal its model, code or data to prove it. This document describes a profile
for **proving policy conformance without disclosing the graph**, using
zero-knowledge proofs (ZKP) and Verifiable Credentials.

It is the privacy-preserving complement to the [Security Model](../03-federation/Security-Model.md):
the Security Model secures *what is exchanged*; attestation lets a party be
*trusted about what it does not exchange*.

---

# 2. The Problem It Solves

Classical assurance requires inspection: "show me your code / your data / your
graph." In B2B federation that is often impossible — the graph is the
intellectual property, and the data is confidential. Yet the consumer still needs
to know, for example:

- "every projection of personal data is governed by a contract";
- "no rule in your model permits onward disclosure for this purpose";
- "your implementation conforms to compliance policy *P*".

Attestation answers these as **proofs about a hidden model**, not disclosures of
it.

---

# 3. How It Works (conceptually)

1. The prover commits to its model by its **Semantic Fingerprint**
   ([MMAS-Interchange](../02-architecture/MMAS-Interchange.md)) — a public,
   tamper-evident handle to a private structure.
2. The prover generates a **zero-knowledge proof** that a stated predicate holds
   over the committed model (e.g. "all `personal-data` projections are
   contract-governed"), revealing nothing else.
3. The proof is packaged as a **Verifiable Credential** issued under the prover's
   [Decentralized Identifier](../06-ecosystem/Decentralized-Registry.md).
4. The verifier checks the proof against the public predicate and the committed
   fingerprint — learning *that the property holds*, not *how*.

The predicate vocabulary aligns with the [Policy Consistency](../02-architecture/Policy-Consistency.md)
rule semantics, so the same rules that are checked internally can be attested
externally.

---

# 4. Use in Federation

- During Trust establishment, a Universe MAY present policy attestations as
  [Trust Evidence](../03-federation/Trust-Model.md), raising the `governance` and
  `semantic` dimensions of the [Trust Vector](../03-federation/Security-Model.md)
  without disclosing its model.
- A [Discovery Document](../03-federation/Discovery.md) MAY advertise which
  attestations a Universe can provide.
- Attestations are revocable and time-bound, like any credential.

---

# 5. Relationship to Disclosure

Attestation never replaces [Consent and Disclosure](../03-federation/Consent-and-Disclosure.md)
for the knowledge that *is* shared; it governs assurance about the knowledge that
is *not* shared. The two compose: share the minimum under contract, and prove the
rest in zero knowledge.

---

# 6. Status

This is a forward-looking **profile**, not a mandate. It depends on a chosen
cryptographic suite and a predicate-proof system, to be specified with the
Security Model's cryptographic profile.

---

# Future Directions

- A concrete **cryptographic profile** (proof system, commitment scheme, DID
  methods), co-developed with the [Security Model](../03-federation/Security-Model.md).
- A **predicate library** for common compliance statements (PII handling,
  retention, onward-disclosure, residency).
- Attestation **chaining** so a federation of universes can present a composite
  proof of end-to-end compliance.

---

# Final Statement

> The strongest trust between rivals is the kind that reveals nothing: prove you
> obey the rules without showing the world you built to obey them.