iDarkPool: Private DeFi for Everyone + Cast-POS: Social Commerce Point-of-Sale

🏆 ETHRome 2025 Submission – Final Submission Version - Submitting 2 Projects

1 - iDarkPool – Private DeFi for Everyone

2 - Cast-POS – Social Commerce Point-of-Sale for Farcaster

FIRST PROJECT NAME - iDarkPool – Private DeFi for Everyone

DESCRIPTION OF THE PROJECT 

Empowering everyday users with secure, confidential, and fair DeFi trading.Built on Base and Arbitrum, inspired by iExec confidential computing.

TELEGRAM USER NAME

tg: @mariocana.eth; @wesley.rios

REPOSITORY WITH THE PROJECT'S CODE

https://github.com/ReageMeuFilho/crypto-brokerage-miniapp

https://github.com/mariocana/idarkpool

DEPLOYED APPLICATION URL

Vercel Test Deployment – iDarkPool Mini-App (placeholder)Arbitrum Sepolia Smart Contracts 

 https://crypto-brokerage-miniapp.vercel.app

CONTRACT ADDRESSES AND CHAINS

Network: Arbitrum Sepolia Testnet

ContractAddressDescription

🧠 iWorker 0x7767E37615C847247d3e54F89294FfB76D913D26 -Processes private order instructions and connects off-chain matching to on-chain logic.

⚖️ DarkPoolSettlement Contract 0xfa5d6c3fdbcf02a9bf7743011fa9b9b91ce452c1 Handles trade verification and settlement execution on-chain.

💵 USDCmock 0x14738fb1b5789e5f67369e65261500c898d84c06 Simulated stablecoin contract for demo trading.

💰 ETHmock0x25c2bc615ba6b0d3e136d58603bc60695f072cefSimulated ETH asset for demo pairing.

BOUNTIES

🟡 iExec – Confidential DeFi ($6,000)

iDarkPool is a Confidential DeFi prototype designed around iExec’s privacy principles:

• Implements DataProtector-compatible encryption for order creation.

• Simulates secure off-chain computation through a mock SGX-based iWorker layer.

• Architecture is fully iExec-ready, enabling future migration to a live SGX worker pool for verifiable confidential execution.

By integrating iExec’s design philosophy, iDarkPool democratizes institutional-grade privacy for everyday DeFi users.

🔵 Base – MiniApp ($5,000)

Built as a Base Mini-App integrated with Farcaster’s social layer, iDarkPool makes DeFi personal and viral:

• Runs natively within social feeds — no friction, no extra wallets.

• Enables “Private Trade Rooms” and “Social Liquidity Challenges.”

• Developed using Base Build and Coinbase Wallet integrations.

A living example of how Base Mini-Apps can drive social, inclusive financial experiences.

⚙️ Arbitrum – Deployment Track ($2,000)

Arbitrum Sepolia powers the on-chain settlement of iDarkPool:

• iWorker and DarkPoolSettlementContract handle end-to-end trade execution.

• Mock tokens (USDCmock, ETHmock) simulate real-world liquidity pairs.

• Low fees, fast confirmation, and complete transparency.

A hybrid DeFi architecture combining off-chain confidentiality and on-chain verifiability — powered by Arbitrum.

INSPIRATION & STORY

Privacy shouldn’t be a privilege — it’s a right.DeFi’s radical transparency has created an uneven playing field:bots exploit, whales dominate, and regular users get front-run.iDarkPool changes that.It’s a Confidential DEX designed for fairness — where encrypted trades ensure your strategy remains your own, and settlements stay transparent for trust.With Base Mini-Apps for reach, iExec for privacy, and Arbitrum for scalability, iDarkPool empowers the everyday individual to participate safely in a new, fair financial system.

TECH STACK

LayerTechnologyFrontendBase Mini-App (Farcaster SDK, React, OnchainKit)BlockchainArbitrum Sepolia (Solidity Smart Contracts) Privacy / ComputeiExec Confidential Architecture (DataProtector schema + mock SGX worker)  Farcaster identityFrameworksVite, TypeScript, Ethers.js

WHAT MAKES IT UNIQUE

• First social Mini-App DEX combining privacy, fairness, and virality.

• Seamlessly integrates iExec, Base, and Arbitrum into one system.

• Built for everyday users, making private DeFi simple, secure, and social.

• Proves that privacy = fairness = accessibility.

VISION BEYOND ETHRome

Participating in ETHRome and working with iExec’s technology has been an amazing experience — one that pushed us to explore the real power of Confidential Computing, understand its potential, and identify where innovation can continue.

We’ve learned a tremendous amount about your platform’s capabilities and limitations, and we now see a much larger opportunity ahead:to evolve iDarkPool into a Confidential Liquidity Network, supporting:

• Private swaps, lending, and yield products.

• Encrypted portfolios and on-chain reputation scoring.

• Expansion into on-chain SMB payments using Base Mini-Apps.

Beyond this, our ultimate goal is to create an automated order book matching system that operates entirely within iExec’s private compute layer.This will require collaboration on both sides — improvements in the platform’s privacy APIs and deeper integration from our architecture.

To support this next step, we are sharing our complete architecture and design documentation for both the front-end and the back-end:

🔗 DeepWiki – Final Submission DarkPool

https://deepwiki.com/reagemeufilho/finalsubmissiondarkpool

🔗 DeepWiki – Pivot Architecture Notes

https://deepwiki.com/reagemeufilho/pivot

These pages contain:

• Full system architecture diagrams (frontend, backend, and contract flow).

• Technical recommendations and improvement proposals for iExec integration.

• References to key design decisions and trade-offs made during the build.

To the iExec team: thank you for this opportunity.We would love to continue collaborating — ideally through a grant or co-development partnership — to bring this vision to life.If you’d like a walkthrough of the code or documentation, we’ll be happy to present it live and discuss our findings in detail.

Together, we can turn Confidential DeFi into a global standard — making privacy, fairness, and trust accessible to everyone.

FINAL MESSAGE FOR JUDGES

iDarkPool unites three forces — Base, iExec, and Arbitrum — to build a fairer financial system.It’s a live, deployable prototype proving that privacy, scalability, and social design can coexist.The future of DeFi is not just open.It’s private, fair, and for everyone. To the iExec team: thank you for opening our eyes to what’s possible.We would be thrilled to continue this work with you — ideally through a grant or co-development initiative — to bring this vision fully to life.

SECOND PROJECT NAME- Cast-POS – Social Commerce Point-of-Sale for Farcaster

DESCRIPTION OF THE PROJECT 

Transforming Farcaster mini-apps into crypto payment terminals with instant QR payments.Built on Arbitrum for fast, low-cost transactions and social, frictionless checkout experiences.

TELEGRAM USER NAME

tg:  @mariocana.eth; @wesley.rios

REPOSITORY WITH THE PROJECT'S CODE

https://github.com/ReageMeuFilho/cast-pos

DEPLOYED APPLICATION URL

• Demo: https://farcaster.xyz/wesleyrios/0x4c7309e0

• Smart Contracts:

  • CastPOS Contract – 0x41E0b9D7750a34FD31E990EfA8a9ab0B7789F29F

  • Mock USDC – 0x11156102a7cb41B90eBc238C37C4103A71C12Edb

CONTRACT ADDRESSES AND CHAINS

Network: Arbitrum Sepolia Testnet

ContractAddressDescription💳 CastPOS0x41E0b9D7750a34FD31E990EfA8a9ab0B7789F29FMain POS smart contract that accepts USDC, emits real-time PaymentReceived events, and manages treasury.💵 Mock USDC0x11156102a7cb41B90eBc238C37C4103A71C12EdbERC-20 test token used for demo payments and contract testing.

BOUNTIES

⚙️ Arbitrum – Deployment Track ($2,000)

Cast-POS is fully deployed on Arbitrum Sepolia, delivering a real-time, event-driven payment system that works for micro-transactions:

• Gas-optimized Solidity contract for low-fee payments (< $0.01).

• PaymentReceived events provide instant UI updates via WebSocket.

• 2–3 second finality creates a seamless retail-like checkout experience.

• Transparent, auditable payment trail through Arbiscan.

Arbitrum’s scalability makes social crypto payments practical and profitable for small merchants worldwide.

🔵 Base – Mini-App (Social & Small Business Track)

Cast-POS runs as a Farcaster-native Mini-App, turning conversations into points-of-sale:

• Social-first UX: merchants share QR codes directly in casts or DMs.

• PWA architecture: installable, offline-ready, no app switching.

• Creator monetization: artists, vendors, and event hosts can receive USDC directly in-chat.

• Designed for the Mini-App – Social and Mini-App – Small Business categories, demonstrating how Base can merge payments with social virality.

This is social commerce reimagined — payments as natural as sharing a link.

INSPIRATION & STORY

The ProblemSmall businesses and creators want to accept crypto but face complexity, hardware costs, and transaction fees.The VisionWhat if crypto payments were as simple as posting a QR code?Cast-POS makes it happen. Any Farcaster Mini-App becomes a point-of-sale. Coffee shops post QR codes for daily sales; creators sell artwork through casts; street vendors accept crypto instantly.With Arbitrum for fast, low-cost transactions and Base for social reach, Cast-POS brings crypto commerce to everyone — no terminals, no friction, no intermediaries.

TECH STACK

LayerTechnologyFrontendNext.js 15, React, TypeScript, Tailwind CSS, shadcn/uiBlockchainArbitrum Sepolia (Solidity 0.8.20, OpenZeppelin)Smart ContractsHardhat 2.x + Ethers v6Web3 Integrationwagmi v2 + viem hooksReal-TimeWebSocket event listeners (useWatchContractEvent)Wallet SupportMetaMask, Coinbase Wallet, WalletConnectPWAService Workers + installable offline supportStandardsEIP-681 (Ethereum Payment URLs / QR Codes)

WHAT MAKES IT UNIQUE

• First social-native POS system for Farcaster Mini-Apps.

• Event-driven architecture—UI reacts instantly to on-chain events.

• Zero infrastructure costs—fully on-chain + frontend.

• Universal QR support—EIP-681 works with any wallet.

• Gas-optimized for micro-payments on Arbitrum L2.

• Transparent audit trail—every payment verifiable on Arbiscan.

• Open source and extensible.

HOW IT WORKS

1. Merchant generates QR code → Encodes EIP-681 transaction for CastPOS.

2. Customer scans with wallet → Wallet decodes function and amount.

3. Smart contract executes → Transfers USDC, logs payment, emits event.

4. Frontend updates in real-time → WebSocket event → instant toast + balance update.

5. Verification → Transaction and proof visible on Arbitrum Sepolia.

End-to-end payment flow completes in ≈ 2–3 seconds.

KEY FEATURES

For Merchants – zero hardware, instant settlement, real-time notifications, social integration.For Customers – familiar wallet UX, fast checkout, on-chain proof, no signups.For Developers – clean code, EIP-681 compliance, event-driven template ready to extend.

VISION BEYOND ETHRome

Participating in ETHRome 2025 and building on Arbitrum has shown us that crypto payments can be simple, social, and ready for everyday commerce.

We see a major opportunity ahead to scale Cast-POS into a complete social commerce layer for the Farcaster ecosystem:

• Phase 1: Deploy to Arbitrum mainnet with real USDC and launch as official Mini-App.

• Phase 2: Add multi-currency support, refunds, tipping, receipts, and analytics.

• Phase 3: Enable multi-merchant accounts, NFT loyalty rewards, subscriptions, and white-label APIs.

To support ongoing development, we’ve documented our architecture and design in detail for judges and partners to review:

These resources include frontend and backend diagrams, technical suggestions, and integration plans to make Cast-POS production-ready.

To the Arbitrum and Base teams: thank you for this incredible hackathon experience. We’ve learned a lot about your platforms — their capabilities and their limitations. We believe there’s an enormous opportunity to work together to bring social crypto commerce to life. If you’re interested in this mission, we’d be thrilled to continue collaborating through a grant or co-development partnership.

Together, we can make crypto commerce as simple and universal as sharing a QR code.

FINAL MESSAGE FOR JUDGES

Cast-POS proves that crypto payments can be simple, fast, and social.Deployed contracts, working demo, and real-time UX show it’s ready for mainnet.With Arbitrum for speed and fees and Base for distribution, we’re building a new foundation for social commerce at scale.The future of commerce is on-chain — accessible, social, and effortless.