Glossary Entry

What is Intent-Evaluated MPC?

Intent-Evaluated MPC requires signing nodes to independently verify the policy authorization hash before contributing partial signatures, adding a second cryptographic verification layer.

Overview

Intent-Evaluated MPC requires signing nodes to independently verify the policy authorisation hash before contributing partial signatures, adding a second cryptographic verification layer.

Standard multi-party computation distributes key shares across a node network and uses threshold mathematics to produce a valid signature — but nodes in a standard MPC setup execute signing when a threshold of partial signatures is reached, without independently checking whether the request is policy-authorised. Intent-Evaluated MPC changes this constraint: each signing node verifies the policy authorisation hash against the request before contributing its partial signature, introducing a verification layer that is independent of the orchestrator.

DeAgenticAI’s Agentic Control Plane [/glossary/agentic-control-plane/] enforces cryptographic policy over AI agent authority — separating what an agent can do from what it is authorized to do — in Web3 and enterprise financial environments. Intent-Evaluated MPC is Layer 7 of that stack, the MPC Distributed Execution layer, and is the component that transforms standard threshold signing into governance-grade signing where each node is an independent verification point — not just a key-share holder.

How does it work?

  1. 1

    Policy hash generation

    The Policy DSL [/glossary/policy-dsl/] rules governing the agent compile to a cryptographic authorisation hash — a deterministic output encoding the governance state at authorisation time. This hash travels with the signing request through the ACP stack.

  2. 2

    Upstream verification

    The proposal passes through Layers 1–6 in sequence: agent identity is established (KYA [/glossary/kya-know-your-agent/]), prompt injection is blocked (Intent Sanitization [/glossary/intent-sanitization/]), governance rules are evaluated (Policy DSL), behavioural anomalies are checked (Fraud Detection), pre-authorised transactions are routed on session keys (Fast-Path Execution), and one key share is anchored to physical hardware (Hardware-Hybrid Custody [/glossary/hardware-hybrid-custody/]). A signing request that reaches Layer 7 carries the policy authorisation hash and has passed all six upstream gates.

  3. 3

    Distribution to the node network

    The signing request is distributed to the t-of-n MPC node network. Each node holds one key share. A threshold of t partial signatures is required to reconstruct the final signature — no single node can produce a valid signature independently.

  4. 4

    Independent node verification

    Each signing node independently verifies the policy authorisation hash and the signing request before contributing its partial signature, using its own local policy state — not a value supplied by the orchestrator. Per Whitepaper §9.2: "Each signing node independently verifies the policy hash and the signing request before contributing its partial signature." A hash mismatch causes the node to withhold its partial signature.

  5. 5

    Threshold reconstruction

    Nodes that pass verification contribute their partial signatures. When t-of-n nodes have contributed, the final signature is reconstructed and the transaction proceeds to chain broadcast. If a mismatch reduces contributing nodes below threshold, the signing ceremony fails and the action is blocked at the cryptographic layer — not at the application layer.

Why does this matter?

Standard MPC protects against key theft: an attacker needs t-of-n key shares to reconstruct the signing key. What it does not protect against is a compromised orchestrator. If the system issuing signing requests is manipulated, a standard MPC network will sign whatever request it receives once the threshold is met — no node independently checks whether the request is policy-authorised.

Intent-Evaluated MPC closes this gap. Each node's independent policy hash verification means a compromised orchestrator cannot fabricate a policy-authorised signing request without nodes detecting the mismatch and withholding their partial signatures. For autonomous AI agents executing on-chain at speed and scale — where a compromised agent could issue signing requests faster than any human review process — this is the architectural guarantee that governance holds even when the application layer fails.

Frequently Asked Questions

What is Intent-Evaluated MPC?

Intent-Evaluated MPC is DeAgenticAI's core security primitive in which MPC signing nodes independently verify the policy authorisation hash before contributing partial signatures — adding a second cryptographic verification layer independent of the orchestrator. It is Layer 7 of the Agentic Control Plane stack (MPC Distributed Execution), and ensures governance rules are enforced at the node level, not just at the application layer.

How does Intent-Evaluated MPC differ from standard threshold MPC?

Standard threshold MPC protects against key theft by distributing key shares — t-of-n nodes must contribute to reconstruct the signing key. It does not verify at the node level whether the request is policy-authorised. Intent-Evaluated MPC adds this check: each node verifies the policy authorisation hash before contributing. A compromised orchestrator submitting a policy-violating request will be rejected by nodes detecting the hash mismatch.

How does Intent-Evaluated MPC relate to Hardware-Hybrid Custody?

Hardware-Hybrid Custody (Layer 6) and Intent-Evaluated MPC (Layer 7) operate in sequence and address two distinct attack surfaces. Layer 6 anchors one key share to physical hardware, preventing cloud-based key theft. Layer 7 requires each node — including the hardware-anchored node — to independently verify the policy authorisation hash before contributing a partial signature, preventing governance bypass via orchestrator compromise. Layer 6 secures key material; Layer 7 enforces policy at signing time.

What happens if a signing node detects a policy hash mismatch in Intent-Evaluated MPC?

The node withholds its partial signature. Because threshold reconstruction requires t-of-n partial signatures, a node withholding drops the count below threshold, preventing the final signature from being assembled. The signing request fails without producing a valid signature, and the action is blocked at the cryptographic layer — not at the application layer. No valid signature means no chain broadcast.

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