TrustVC EIP-7702 Smart Account

Gasless trade document operations on TrustVC via EIP-7702 (smart account delegation) and ERC-4337 (account abstraction). Deployed on Sepolia testnet.

Overview

This package provides three contracts:

Contract	Role
EIP7702Implementation	Shared smart account logic that EOAs delegate to via EIP-7702
PlatformPaymaster	Per-platform ERC-4337 paymaster — sponsors gas for registry and title escrow operations
PlatformAccountFactory	Deploys PlatformPaymaster clones cheaply via EIP-1167 (Clones.cloneDeterministic)

How it works

1. Delegate — An EOA signs an EIP-7702 authorization pointing to EIP7702Implementation. The EOA's code becomes 0xef0100 || impl_address, giving it full smart-account capabilities while keeping its original private key.
2. Deploy paymaster — A platform calls PlatformAccountFactory.deployPlatformPaymaster(). A minimal-proxy clone (~55k gas vs ~1.5M for a full deploy) is initialized with the platform's owner address, daily ETH limit, and TDoc deployer.
3. Gasless ops — Users submit UserOperations through a bundler (Pimlico). The paymaster validates and sponsors:
   • Path A — Calls to authorized registries or title escrows (beneficiary/holder/owner only, daily limit enforced)
   • Path B — deployRegistry (credit-gated) and mintDocument (MINTER_ROLE gated) on the paymaster itself

Contracts

EIP7702Implementation

EIP-7702 smart account using OpenZeppelin's Account, SignerEIP7702, and ERC7821. Deployed once; EOAs point to it via authorization.

• entryPoint — immutable, baked into bytecode at deploy time
• Execution via ERC7821 batch execute
• Signature validation: signer must equal address(this) (the delegating EOA)

PlatformPaymaster

Per-platform ERC-4337 paymaster cloned from a shared implementation.

State

Variable	Description
tdocDeployer	TDocDeployer contract that mints registry clones
authorizedRegistries	Registries whose calls this paymaster will sponsor
authorizedTitleEscrows	Title escrows whose calls this paymaster will sponsor
authorizedCallers	Addresses (beneficiary/holder) allowed on Path A
userWhitelist	Deployment credits per user (max 3)
documentsMinted	Count of documents minted per caller
dailyLimit	Max ETH sponsored per user per day

Key functions

• initialize(owner, dailyLimit, tdocDeployer) — called once by the factory after clone; guarded by owner() == address(0)
• deployRegistry(impl, name, symbol) — deploys a TradeTrust registry, consumes one credit, auto-authorizes it
• mintDocument(registry, beneficiary, holder, tokenId, remark) — mints a document, auto-authorizes beneficiary + holder + title escrow
• setUserWhitelist / removeUserFromWhitelist — manage deployment credits (onlyOwner)
• addRegistry / removeRegistry — manage authorized registries (onlyOwner)
• addTitleEscrow / removeTitleEscrow — manage authorized title escrows (onlyOwner)
• addAuthorizedCaller / removeAuthorizedCaller — manage Path A callers (onlyOwner)
• setDailyLimit — update daily spend cap (onlyOwner)
• getUserDailySpend(user) — returns (spent, limit, resetsAt)

PlatformAccountFactory

Deploys PlatformPaymaster clones deterministically.

• deployPlatformPaymaster(platformAddress, dailyLimit, salt) — clones the implementation and calls initialize
• computePaymasterAddress(salt) — predict the clone address before deployment
• updateTdocDeployer(addr) — update TDoc deployer (onlyOwner)
• updatePaymasterImplementation(addr) — upgrade the implementation for future clones (onlyOwner)

Deployed addresses (Sepolia)

Contract	Address
EIP7702Implementation	0xa46EC3920Ac5fc54F4bA33185A91ae250aDF59B8
PlatformPaymaster (implementation)	0xa24695178ea881ab7d4d105106e4906a8da4752b
PlatformAccountFactory	0x7e9ef6363180baa744eb32ceab367a44f52adc9f
TDocDeployer	0x64bc665056DC8bE4092e569ED13a7F273Be28cD2
EntryPoint v0.8	0x4337084D9E255Ff0702461CF8895CE9E3b5Ff108

Installation

npm install @trustvc/eip7702

Development

Prerequisites

• Node.js 18+
• A Sepolia RPC URL (e.g. Infura)
• A Pimlico API key for bundler access

Setup

npm install
cp .env.example .env   # fill in PRIVATE_KEY, SEPOLIA_RPC_URL, PIMLICO_API_KEY

Build

npm run build          # compile contracts + generate ABIs + bundle JS
npm run build:sol      # compile contracts only
npm run build:abis     # generate ABI TypeScript files only

Test

npm test               # runs all 45 hardhat tests

Deploy (Sepolia)

Deploy in order:

# 1. Deploy the shared PlatformPaymaster implementation
npx hardhat run scripts/deployImplementation.ts --network sepolia

# 2. Deploy the factory (add PAYMASTER_IMPLEMENTATION to .env first)
npx hardhat run scripts/deployFactory.ts --network sepolia

# 3. Clone a paymaster for your platform (add FACTORY_ADDRESS to .env first)
npx hardhat run scripts/deployPlatformPaymaster.ts --network sepolia

# 4. Stake the paymaster on the EntryPoint
npx hardhat run scripts/stakePlatformPaymaster.ts --network sepolia

Mint a document gaslessly

npx hardhat run scripts/mintDocumentGasless.ts --network sepolia

Environment variables

Variable	Description
PRIVATE_KEY	Deployer wallet private key
SEPOLIA_RPC_URL	Sepolia RPC endpoint
PIMLICO_API_KEY	Pimlico bundler API key
TDOC_DEPLOYER_ADDRESS	Deployed TDocDeployer address
PAYMASTER_IMPLEMENTATION	PlatformPaymaster implementation address
FACTORY_ADDRESS	PlatformAccountFactory address
PAYMASTER_ADDRESS	Deployed paymaster clone address
EIP7702_IMPL_ADDRESS	EIP7702Implementation address

Tech stack

• Solidity ^0.8.28 · OpenZeppelin Contracts v5 · @account-abstraction/contracts v0.8
• Hardhat · hardhat-toolbox-viem · Viem · Pimlico bundler
• EIP-7702 · ERC-4337 · EIP-1167 minimal proxy · Sepolia testnet