PrivacyARC Overview

PrivacyARC is privacy infrastructure on Arc Chain. It makes stablecoin settlement confidential by construction — FHE-encrypted balances, ZK-shielded transfers, and relay origin protection — and exposes it through two payment surfaces: Private Pay for people, and Agent Rails for machines.

What PrivacyARC is

PrivacyARC is a privacy layer for USDC settlement on Arc Chain. Balances are stored as FHE ciphertexts (euint64) so amounts are never public, transfers settle through a ZK shielded pool with commitments and nullifiers, and a relay network strips transaction origin. The result: stablecoin payments that behave like cash — final, programmable, and private.

What you can do today

Product hierarchy

1. Privacy infrastructure — the FHE + ZK + relay core. Everything else is built on it.
2. Private Pay — the consumer product: phone-number payments, claim links, pay links, withdrawals.
3. Agent Rails — the extension: private x402 payments, ERC-8004 identity/reputation, ERC-4337 passports with hard caps.

Private Pay

Send USDC to any phone number. The recipient claims from an SMS link — wallets optional, privacy default.

How a payment works

1. Prepare — enter a phone number and amount in the Dashboard. The number is salted and hashed (phoneHash); the cleartext number never touches the chain.
2. Choose a privacy tier — Full, Semi, or Standard (see below).
3. Review — confirm amount, tier, and escrow terms. You sign one transaction.
4. Lock — USDC moves into the SMS escrow contract against the phoneHash.
5. Claim — the recipient gets an SMS with a claim link, verifies possession of the number, and withdraws to any wallet — or to a fresh embedded wallet created on the spot.
6. Refund — if the payment is never claimed, you can refund it back to your own balance after the escrow window.

Privacy tiers

Every tier keeps balances encrypted. Higher tiers add shielded-pool routing and relay origin protection for the transfer itself.

Pay links

Create a one-time link for a fixed amount and share it anywhere. The payer opens the link, reviews, and settles. Unclaimed links auto-refund after 7 days.

Withdrawals

Move USDC from your encrypted PrivacyARC balance back to any public Arc address. Withdrawals from the shielded pool go to a fresh address you choose, preserving the privacy gained inside the pool.

Agent Rails

An extension of the privacy core for autonomous agents: private x402 settlement, portable identity and reputation, and hard on-chain spend limits.

Private x402 payments

x402 is the HTTP-native payment handshake: a service responds 402 Payment Required, the agent pays, and retries with proof. PrivacyARC settles x402 payments through the same confidential core, so an agent's payment graph — what it buys, from whom, how much — stays private.

ERC-8004 identity & reputation

Each agent registers an ERC-8004 identity: a portable, on-chain handle that accumulates reputation from completed private settlements. Counterparties can check standing without seeing payment contents.

ERC-4337 agent passports

An agent passport is an ERC-4337 smart account issued to an agent, controlled by your session keys and bounded by hard spend caps enforced on-chain — per-transaction, per-day, and per-counterparty. Caps are contract-enforced, not policy-enforced: the agent cannot exceed them even if its own logic is compromised.

Kill switch

Every passport has an owner-controlled kill switch. Revoking it freezes the agent's ability to transact immediately, on-chain, without touching the agent's runtime.

Using the SDK

import { PrivacyARCAgent } from "@privacyarc/sdk";

const agent = new PrivacyARCAgent({
  passport,      // ERC-4337 smart account with hard caps
  sessionKey,    // scoped session key for the agent runtime
});

// Private x402 fetch — pays confidentially, respects caps
const res = await agent.fetch("https://api.example.com/paid-endpoint");

SDK access is rolling out with the Agent Rails testnet phase. The Dashboard's AI/x402 terminal shows configuration-required states until contracts are configured.

Testnet Guide

PrivacyARC is live on the Arc public testnet. Everything you can do on testnet today, and how to try it.

Network details

The Connect Wallet button in the navigation adds or switches to Arc Testnet automatically in MetaMask.

What to test

1. Private Core — encrypt a balance, send a shielded transfer, withdraw to a fresh address.
2. Consumer Reach — send a phone-number payment, claim it from the SMS link flow, refund an unclaimed payment.
3. Privacy tiers & relay — compare Full / Semi / Standard on the same payment.
4. Agent Rails preview — create a passport, set hard caps, preview a private x402 settlement in the terminal.

Mainnet Transition

Arc public mainnet launches September 16, 2026. PrivacyARC's roadmap is staged so every layer is proven on testnet before it settles real value.

Roadmap

1. Private Core — FHE confidential balances, ZK shielded settlement, and the PARC fee flywheel.
2. Consumer Reach — SMS escrow, claim links, pay links, and refunds.
3. Privacy Tiers & Relay — Full / Semi / Standard tiers with relay origin protection.
4. Agent Rails — private x402, ERC-8004 identity, ERC-4337 passports.
5. Arc Mainnet Launch — September 16, 2026.

What changes at mainnet

The same contracts and the same interfaces move from chain 5042002 to Arc mainnet (5042). Testnet state does not carry over: balances, escrows, and passports are re-initialized on mainnet. The Dashboard will prompt a network switch at launch and clearly label which network you are on at all times.

PARC fee flywheel

Protocol fees route to the PARC flywheel: buyback, burn, and rewards for the privacy core's usage. Fee parameters are published with the mainnet configuration.

Architecture

Four contracts and a relay network, composed into one confidential settlement core on Arc Chain.

Components

Chain configuration

Security & audits

Contract audits are scheduled per the roadmap, ahead of the September 16, 2026 mainnet launch. Audit reports will be linked here as they are published.

FAQ