The Proof-of-Action Protocol Specification

"Traditional distributed ledgers excel at recording the transfer of digital abstractions within their closed state machines. Acta connects blockchain consensus directly with reality: money moves when physical deeds or verified digital deliverables occur."

On traditional blockchains, escrows are hampered by high transaction gas ($2–$15 per state update on EVM chains), slow block times (12–15 seconds), and opaque dispute systems. Acta leverages the Nimiq Proof-of-Stake (Albatross) consensus engine to achieve sub-second micro-blocks and deterministic finality with micro-fees of 0.0001 NIM.

Because transaction costs on Nimiq are negligible, micro-covenants become viable: lending a power tool for two hours, sponsoring a neighborhood park cleanup, placing an unforgeable cryptographic proximity token at a secret location, or commissioning a global open-source bug fix.

§ 1.2 Traditional Escrow Failure Modes vs. Acta

§ 1.3 Local Proximity vs. Global Remote Deeds

A common misconception is that Acta only supports physical, in-person hardware handoffs between neighbors. This is only one subset of its capability. The protocol spans two complementary vectors:

§ 1.4 Guarantees, Tradeoffs & Constraints

Acta does not compromise on architectural honesty. We disclose the real-world engineering constraints:

§ 2.1 The Nimiq PoS Albatross Engine

Acta runs atop Nimiq's second-generation consensus mechanism: Albatross. Albatross is a state-of-the-art, optimistic Proof-of-Stake algorithm capable of achieving thousands of transactions per second with sub-second micro-blocks.

§ 2.2 Embedded Nimiq Pay Mini-App Sandbox

Acta detects when executed inside the official Nimiq Pay mobile application via the injected global bridge (window.nimiq).

All covenant collateral and bounty funds are held by the autonomous protocol address:

The vault operates non-custodially: funds can only be disbursed when cryptographic proof (signed QR, geofence coordinate, AI verdict, or sponsor signature) is verified by the backend engine.

§ 2.4 Zero-Cron Settlement Architecture

Borrow high-value physical hardware (camera gear, power tools, drones, measurement instruments) with zero centralized paperwork. Collateral is locked securely into the autonomous vault and returned instantly upon scanning the owner's cryptographic return QR code.

Photo bounties are judged by an autonomous multi-modal AI vision model: Qwen 3.6 35B FP8 running on dedicated Hetzner cloud inference (https://inference.hetzner.com/api/v1).

Physical proximity transfers and return receipts rely on ephemeral Ed25519-signed payloads.

• Single-use cryptographic nonce burned in database upon redemption to guarantee zero replay attacks.
• 10-minute expiry window (exp = Date.now() + 600000).
• Full WebRTC camera scanner with automatic fallback to native file upload.

For regional bounties (street cleanups, physical checkpoints, event attendance), Acta verifies physical presence using the Haversine Great-Circle formula:

Custom commissions where an algorithmic or AI oracle cannot evaluate subjective nuance. The challenger submits proof in Inbox, and the sponsor clicks "Approve & Release Vault Funds", broadcasting the release transaction sub-second.

§ 3.6 Online Ventures & Digital Bounties (100% Global)

§ 4.1 The 4 Contract Toggles

In the active dashboard, covenants are partitioned into 4 distinct views:

To eliminate notification noise, every toggle displays a dynamic numerical badge (1, 2) indicating how many items require user attention. The badge automatically dismisses as soon as the user opens that tab, tracking view state locally in memory.

Every covenant transitions deterministically through 6 formal stages: open → locked → settling → released (or disputed / refunded).

§ 4.4 Unreturned Item Claims & 48-Hour Grace Period

Acta does not rely on subjective star ratings or easily gamed reviews. Trust is derived algorithmically from mathematical facts etched in the acts ledger:

Trust score directly lowers required collateral locks for equipment borrowing:

§ 5.3 The 5 Sovereign Privileges / Rites

§ 5.5 Career Milestones & Recurring Drips

Clients authenticate by signing a single-use nonce challenge with their Nimiq Ed25519 keypair.

// 1. Request challenge nonce
const { nonce } = await fetch('/api/auth/challenge').then(r => r.json());

// 2. Sign message via Nimiq Keyguard or window.nimiq
const message = `Acta login\n\nNonce: ${nonce}`;
const { publicKey, signature } = await signMessage(message);

// 3. Verify signature & establish session
const res = await fetch('/api/auth/verify', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ publicKey, signature, nonce }),
});
const { address, token } = await res.json();
// Store token and transmit via Authorization: Bearer <token>