Architecture

How ERC-7984, ERC-8004, and ERC-8183 form a complete privacy layer for all agent payment protocols.

Protocol Stack

MARC Protocol is a layered architecture. Each layer solves a specific problem, and they compose together into a complete privacy-preserving agent economy.

+--------------------------------------------------+
|  Agent Payment Protocols                         |
|  x402 · MCP · MPP · A2A · AgentKit              |
|  Virtuals GAME · OpenClaw · (any future proto)   |
+--------------------------------------------------+
|  ERC-8183: Agentic Commerce                      |
|  (Job escrow + completion payments)              |
+--------------------------------------------------+
|  ERC-8004: Identity + Reputation                 |
|  (Agent discovery + trust)                       |
+--------------------------------------------------+
|  MARC Protocol: Amount Privacy Layer             |
|  (FHE encrypted balances + transfers)            |
+--------------------------------------------------+
|  Zama fhEVM (EVM, SVM, and future VMs)           |
+--------------------------------------------------+
|  Settlement Chains                               |
|  Ethereum · Base · Arbitrum · Solana · ...       |
+--------------------------------------------------+

Payment Flow

A typical payment flow using MARC Protocol (shown with x402, but the same privacy layer applies to MCP, A2A, and all other supported protocols):

Client (Agent A)                          Server (Agent B)
    |                                          |
    |-- GET /api/data ----------------------->|
    |<--- 402 + FhePaymentRequired ------------|
    |                                          |
    |  1. fhevm.encrypt(amount)                |
    |  2. cUSDC.confidentialTransfer(to, enc)  |
    |  3. verifier.recordPayment(              |
    |       payer, server, nonce, minPrice)    |
    |                                          |
    |-- Retry + Payment header -------------->|
    |   [Server verifies:                      |
    |    - ConfidentialTransfer event           |
    |    - PaymentVerified event (minPrice)]   |
    |<--- 200 + data -------------------------|

Core Contracts

The protocol uses two core contracts plus four supporting contracts:

Contract	Standard	Purpose
ConfidentialUSDC	ERC-7984	Wrap/unwrap USDC, encrypted transfers, fee collection
X402PaymentVerifier	x402	Nonce registry, batch prepayment, price verification
AgentIdentityRegistry	ERC-8004	Agent registration, wallet linking
AgentReputationRegistry	ERC-8004	Proof-of-payment feedback scoring
AgenticCommerceProtocol	ERC-8183	Job escrow, lifecycle management
MockUSDC	ERC-20	Test USDC token (Sepolia only)

ERC-7984: Confidential Token

The foundation layer. ConfidentialUSDC implements the ERC-7984 standard from OpenZeppelin Confidential Contracts. It wraps plaintext USDC into FHE-encrypted cUSDC.

* Balances stored as euint64 (encrypted 64-bit integers)
* Transfers use FHE arithmetic, no plaintext amounts on-chain
* Silent failure. Insufficient balance transfers 0 (no revert = no info leak)
* Operators. Approve third parties to transfer on your behalf (with expiry)

ERC-8004: Agent Identity

Agents register their identity and capabilities on-chain. The registry links agent metadata URIs to wallet addresses, enabling discovery and trust scoring.

* Register agent with JSON metadata URI
* Link wallets to agent IDs
* Reputation via proof-of-payment feedback (score 1-5, tags)
* Identity is public by design, only amounts are encrypted

ERC-8183: Agentic Commerce

Job escrow for multi-step agent workflows beyond simple API payments.

Job Lifecycle

Open→Funded→Submitted→Completed

Can also reach: Rejected (by client or evaluator) | Expired (timeout + client claims refund)

Fee Structure

Operation	Fee	Notes
Wrap (USDC to cUSDC)	max(0.1%, 0.01 USDC)	Deducted before minting
Transfer (cUSDC to cUSDC)	FREE	Encrypted peer-to-peer
Unwrap (cUSDC to USDC)	max(0.1%, 0.01 USDC)	Deducted from cleartext
Job completion (ERC-8183)	1% platform fee	Deducted from escrow release

Design Philosophy

Token-centric, not pool-based

Agents hold encrypted tokens in their own wallets. No shared pool means no custodial risk and no single point of failure.

Free transfers incentivize staying encrypted

Zero-fee transfers between agents encourages staying in the cUSDC layer, increasing protocol stickiness.

Standards-based composability

Building on established ERCs means any wallet, framework, or tool can integrate MARC Protocol.

Multi-Chain and Multi-VM Vision

Zama is expanding FHE technology beyond EVM to other virtual machine environments, including Solana (SVM) and more. MARC Protocol follows Zama everywhere, not limited to EVM chains.

Environment	Status	Impact
Ethereum (EVM)	Live (Sepolia)	Largest DeFi TVL
Base (EVM)	Planned	Leading agent payment chain (Coinbase)
Arbitrum (EVM)	Planned	Largest L2 by TVL
Solana (SVM)	Planned	High-throughput agent ecosystem
Future VMs	Planned	Wherever Zama deploys FHE

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