🛡️ Shield Poker: Privacy-Preserving Poker with On-Chain Social Identity

Live Project Link: https://shield-poker.vercel.app/

Shield Poker is a decentralized, P2P Texas Hold'em game built on Solana. It solves the "on-chain leakage" problem using MagicBlock's Ephemeral Rollups (TEE) for private gameplay and Tapestry Protocol for a persistent, decentralized social layer.

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🎮 Key Features

1. Cryptographic Privacy (Powered by MagicBlock)

• Zero-Leaking Hands: Player hole cards are processed within a Trusted Execution Environment (TEE) using Intel TDX. Cards are never visible on L1 Explorers.
• Lightning Speed: Experience ~50ms execution for betting, checking, and folding—eliminating L1 latency.
• Trustless Settlement: Funds are held in an L1 Vault and only dispersed after the TEE securely settles the game outcome.

2. Social & Reputation Layer (Powered by Tapestry)

• Persistent Player Profiles: Every player has a unique Tapestry identity with a username, bio, and avatar.
• Career Stats Tracking: Performance is recorded on-chain. Profiles keep a permanent record of total_games_played, games_won, and games_lost, updated automatically upon game resolution.
• Decentralized In-Game Chat: A real-time chat system built on Tapestry's social graph. Each game creates a "Content" thread where player messages are pushed as "Comments," ensuring a censorship-resistant table banter.

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📺 Project Demo

🎥 Presentation Video

Watch the Demo

📸 Product Screenshots

1. Poker HomePage

Browse live games and completed games.

2. Private Gameplay & Chat

Joined players can chat and take actions such as fold, check, call or bet amount.

3. Game Result/Showdown Phase

See which player won and how much

4. Player Profile Page

View your tapestry Player Profile Stats

5. Create Player Profile Modal

Create a Player Profile first to host or play a poker game

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🎯 The Problem

On standard blockchains, all state is public. For games like Poker, this is a non-starter:

1. Card Privacy: If your hand is on-chain, anyone can see it.
2. Latency: Waiting 400ms - 2s for every bet kills the game flow.
3. Cost: Transaction fees for every "Check" or "Small Bet" add up quickly.

🏗️ The Solution: MagicBlock PER

Shield Poker moves the sensitive game logic into a hardware-secured Trusted Execution Environment (TEE) using Intel TDX.

Technical Deep Dive

1. Real-Time Privacy (Intel TDX TEE)

The game logic runs within a TEE validator. This ensures that even the validator operator cannot peek at the memory where player hands are processed. We use the #[ephemeral] attribute to mark accounts that should exist primarily in the TEE for speed.

2. Protocol-Level Access Control (ACL)

Instead of just client-side encryption, Shield Poker uses MagicBlock's Permission Program (ACL):

• Public Accounts: The Game account (pot, community cards) has a public ACL.
• Private Accounts: Each PlayerState (holding the hole cards) is protected by a restricted ACL. Only the specific player holding the corresponding TEE authorization token can read their own state.

3. Fast State Settlement

By delegating accounts to the TEE, we achieve ~50ms execution. Once the "Showdown" occurs, the commit_game instruction triggers a state settlement:

• Final winner is determined in the TEE.
• The state is "committed" and "undelegated" back to Solana L1.
• Funds are distributed from the L1 Vault.

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🏗️ Technical Architecture

MagicBlock PER (Private Ephemeral Rollups)

Shield Poker uses the #[ephemeral] attribute to mark sensitive game accounts.

• Access Control: Each PlayerState is protected by a restricted ACL. Only the authorized player can read their own hole cards within the TEE.
• Two-Phase Commit:
  1. TEE Phase: Cards are dealt, and betting occurs at high speed.
  2. L1 Phase: Once the game concludes, the TEE settles the state back to Solana L1 for fund distribution.

Architecture Diagram

sequenceDiagram
    participant P1 as Player 1 (Dealer)
    participant P2 as Player 2
    participant TEE as MagicBlock TEE (Intel TDX)
    participant L1 as Solana L1

    P1->>L1: Initialize Game & Vault
    P2->>L1: Join Game
    Note over P1, P2: Setup Delegation & ACLs
    P1->>TEE: Shuffle & Deal (Private)
    Note right of TEE: Cards stay in TEE memory
    P1->>TEE: Action: Bet (50ms)
    P2->>TEE: Action: Call (50ms)
    Note over TEE: Phase Advance (Flop/Turn/River)
    TEE->>L1: #[commit] Settle Final State
    L1->>P1/P2: Distribute Pot

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Tapestry Social Graph

• Idempotent Stats: Game results are pushed to Tapestry using a secure RESTful API, ensuring career stats are updated exactly once per game resolution.
• Chat Workaround: Tapestry "Content" represents the Game Table, and "Comments" represent the real-time messages, creating a fully on-chain chatroom without a dedicated chat protocol.

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🚀 Getting Started

Prerequisites

• Solana CLI & Anchor 0.32.1
• MagicBlock TEE Authorized Wallet
• Tapestry API Credentials

Installation

1. Clone the repo
2. Setup Program:

   anchor build
   anchor deploy

3. Frontend Configuration: Create a .env.local in app/:

   NEXT_PUBLIC_TAPESTRY_API_KEY=your_key
   NEXT_PUBLIC_TAPESTRY_API_URL=https://api.tapestry.com
   RPC_URL=your_rpc

4. Launch:

   cd app
   npm install
   npm run dev

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🏆 Hackathon Submission

This project is submitted for the following tracks:

• MagicBlock Track: For pioneering TEE-based private gaming on Solana.
• Tapestry Track: For building a comprehensive on-chain social layer including profiles, career stats, and decentralized chat.

Key Innovations

• The "Invisible" Hand: First poker game where cards are cryptographically hidden but execution is instant.
• Persistent Professionalism: Tapestry integration ensures players carry their reputation from table to table.
• Consolidated UX: A unified workflow that handles TEE authorization and game mechanics in a single, intuitive interface.

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📄 License

MIT © 2026 Shield Poker Team