Pillar 03 — Agent Authority Proof

Agent Authority Proof.

Prove an agent's authority without handing it the keys.

Give an AI agent a cryptographic proof of who it acts on behalf of and how far its scope reaches — without ever handing over a signing key. One of the four axes that make up the Lemma trust infrastructure.

Answering the questions being asked most urgently right now

We don't want to hand keys to autonomously running AI agents

We want to verify the authority chain across multi-tier agents after the fact

We need a mechanism to stop over-limit and out-of-scope actions

01 · What Agent Authority Proof is

Prove delegated authority alone, without handing over a key.

Delegator, role, scope, limit, and validity are fixed in a cryptographic proof. The AI agent acts only within scope, and every action becomes verifiable.

Delegator

Person / organization

Defines the role, scope, limit, and validity period granted to the AI agent.

The private key stays with the delegator

Lemma

Issues the authority as a cryptographic proof

1Fix the authority with the delegator's signature

2Parameterize scope, limit, and validity

3Hand it to the agent as a ZK proof

The key itself is never handed over

AI agent

Acts without a key

delegatedByceo@org.jp

roleprocurement

spendLimitUSDC5000

scopevendor-2026

validUntil2026-12-31

Out-of-scope actions are impossible

Think of it like a power of attorney.

To let someone advance a contract while you're away, you draft a power of attorney that spells out "the scope of the delegated authority" and "the expiry" — have you ever done something like this? Lemma's Agent Authority Proof uses the same mechanism for AI agents. Without handing over the key itself, it carries only "within this scope, until this expiry, in this role" as a cryptographic proof.

What is disclosed

The scope of authority + the proof

✓delegatedBy (the delegator's signature)
✓role / scope (role and scope)
✓spendLimit / validUntil (limit and expiry)
✓The cryptographic proof of authority (independently verifiable)

What happens with this mechanism

✓The AI agent can act on behalf within scope, without holding a key

✓The private key stays with the delegator, so leakage risk is structurally absent

✓Over-limit and out-of-scope actions are cryptographically rejected

✓The authority chain across multi-tier agents can be independently verified after the fact

Run autonomous agents without handing over a key.

→Independently verify the chain across multi-tier agents after the fact

→Stop over-limit and out-of-scope actions by construction

→Key-leakage risk disappears from the structure of the work

02 · How it differs from existing approaches

How it differs from API keys, OAuth, and RBAC.

Existing authority management either "hands over a key" or "stays self-contained within a system." The era of autonomous AI agents demands "acting on behalf without handing over a key" — and that needs a different structure.

Approach

Acts on behalf within scope

Key stays with delegator

Independently verifiable

Cryptographic proof

Handing over an API key directly

✓

✗

OAuth token

✓

△

✗

RBAC (in-system permissions)

△

✓

✗

Lemma Agent Authority Proof

✓

03 · Position in the trust infrastructure

P3 is one of the four axes that make up the Lemma trust infrastructure.

P1 Origin P2 AI P3 Authority P4 Attributes

See the full trust infrastructure →

04 · Use in practice

Business scenarios that use this axis.

P3 · A2A

Multi-agent workflows

P3 · Treasury

Delegated treasury

P3 · Expenses

Agent expense approval

See all use cases →

05 · Technical reference

Proprietary cryptography to prove delegated authority without handing over a key.

Delegator signature

Cryptographically fixes the issuer of the authority. Who delegated it can be independently verified by a third party after the fact.

Parametric authority

Role, scope, limit, and validity are parameterized. Anything exceeding them is cryptographically detected and rejected before execution.

ZK authority proof

The key itself is never handed over; only the fact that "this agent may act on behalf within this scope" is passed to the agent as a ZK proof.

// your.agent.v1 — Lemma canonical schema
{
  "$schema": "your.agent.v1",
  "delegatedBy": "ceo@org.jp",
  "role": "procurement",
  "spendLimitUSDC": 5000,
  "scope": "vendor-list-2026",
  "validUntil": "2026-12-31",
  "issuer": "org.jp",
  "zk_proof": "0x9c4f...e7d2"
}

Developer guides for implementing P3