blockmsg

End-to-end encrypted messaging powered by Fully Homomorphic Encryption (FHE)

App • Documentation • Twitter • Powered by Zama

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🔐 What is blockmsg?

blockmsg is the first fully homomorphic encrypted (FHE) messaging platform built on blockchain. Your messages are encrypted end-to-end, and not even our servers can read them – because we literally have no servers storing your data.

Unlike apps that say "we don't read your messages," blockmsg is mathematically designed so that reading your messages is impossible.

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✨ Features

Feature	Description
🔐 FHE Encryption	Messages encrypted in your browser using Fully Homomorphic Encryption before being stored on-chain
💥 Self-Destruct Messages	Set messages to auto-delete after a set time – guaranteed by smart contract
👛 Wallet Identity	No phone numbers or emails – just connect your wallet and start messaging
🛡️ Zero Access	We have no servers, no database, no access to your messages
⛓️ On-Chain Storage	All messages stored on the Ethereum Sepolia blockchain
🔒 Permissionless	No one can ban you or censor your messages

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📊 How It Compares

Feature	Web2 (WhatsApp, Telegram)	Standard Web3	blockmsg (FHE)
Message Privacy	❌ Company can read	❌ Everyone can read on-chain	✅ Only sender & recipient
Encryption	Server-side (breakable)	None (plaintext)	Fully Homomorphic (unbreakable)
Data Storage	Centralized servers	Decentralized but public	Decentralized & encrypted
Censorship	Platform can ban you	Permissionless	Permissionless
Self-Destruct	Server-dependent	Not possible	✅ On-chain guaranteed
Government Access	✅ Backdoors possible	✅ Public chain explorer	❌ Cryptographically impossible

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🏗️ Architecture

Encryption Flow

┌────────────────────────────────────────────┐
│               SENDER                       │
│                                            │
│  Plaintext ───▶ FHE Encrypt (in browser)   │
│  "Hello!"                                  │
└─────────────────────┬──────────────────────┘
                      │ Encrypted
                      ▼
┌────────────────────────────────────────────┐
│              BLOCKCHAIN                    │
│                                            │
│  [0x3f8a...] [0x9c2b...] [0x1d4e...]      │
│                                            │
│  • Everyone can see this data              │
│  • NO ONE can read it without wallet key   │
│  • Protected by FHE encryption             │
└─────────────────────┬──────────────────────┘
                      │
                      ▼
┌────────────────────────────────────────────┐
│        RECIPIENT (wallet signature)        │
│                                            │
│  Ciphertext ──▶ Decrypt ──▶ "Hello!"       │
│                                            │
│  Only possible with recipient's wallet key │
└────────────────────────────────────────────┘

Self-Destruct Flow

sequenceDiagram
    participant Sender
    participant Contract
    participant Recipient
    
    Sender->>Contract: Send encrypted message + expiry time
    Contract->>Contract: Store message with expiry timestamp
    Recipient->>Contract: Request message decryption
    Contract->>Contract: Check if expired
    alt Not Expired
        Contract->>Recipient: Return encrypted data
        Recipient->>Recipient: Decrypt message
    else Expired
        Contract->>Recipient: Return empty (destructed)
    end

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🔍 Who Can Read Your Messages?

Actor	Access Level
🔍 Block Explorers	❌ See only encrypted gibberish
⛏️ Miners / Validators	❌ See only encrypted gibberish
👨‍💻 blockmsg Team	❌ Zero access - no keys, no servers
🏛️ Governments	❌ Cryptographically impossible
📤 You (Sender)	✅ Full access with your wallet
📥 Recipient	✅ Full access with their wallet

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🗄️ Zero-Database Architecture

blockmsg has NO backend database. Your data lives in two places only:

1. Your Browser (localStorage)

┌─────────────────────────────────────────┐
│           YOUR BROWSER ONLY             │
├─────────────────────────────────────────┤
│  • Decrypted messages (after reveal)    │
│  • Contact nicknames                    │
│  • Read/unread status                   │
│  • DM preferences (allow/block lists)   │
│  • Transaction history cache            │
└─────────────────────────────────────────┘
         ⬆️ Only YOU can access this
         ❌ We have ZERO access
         ❌ No server stores this

2. Blockchain (FHE Encrypted)

┌─────────────────────────────────────────┐
│           ETHEREUM BLOCKCHAIN           │
├─────────────────────────────────────────┤
│  • Encrypted message content (FHE)      │
│  • Sender/recipient addresses           │
│  • Timestamps                           │
│  • Self-destruct expiry times           │
└─────────────────────────────────────────┘
         👀 Anyone can see this data
         🔒 NO ONE can read it (encrypted)
         ✅ Only sender & recipient can decrypt

What This Means

Data Type	Storage	Who Can Access
Your preferences	Your browser	Only you
Decrypted messages	Your browser	Only you
Encrypted messages	Blockchain	No one (until decrypted)
Contact names	Your browser	Only you

⚠️ Important: If you clear your browser data, your local preferences are lost forever. We cannot recover them because we never had them.

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🛠️ Tech Stack

Technology	Purpose
fhEVM by Zama	Fully Homomorphic Encryption virtual machine
Solidity	Smart contracts for encrypted message management
Next.js	Frontend application framework
fhevmjs	Client-side FHE encryption library
RainbowKit	Wallet connection and management
Tailwind CSS	Utility-first styling

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🚀 Quick Start

Prerequisites

• Node.js (v18 or higher)
• pnpm package manager
• MetaMask browser extension

Installation

# Clone the repository
git clone https://github.com/Gutslabs/blockmsg.git
cd blockmsg

# Initialize submodules
git submodule update --init --recursive

# Install dependencies
pnpm install

Development

# Start the development server
pnpm start

Visit http://localhost:3000 in your browser.

Production Deployment

Set the following environment variables:

NEXT_PUBLIC_ALCHEMY_API_KEY=your_alchemy_key
NEXT_PUBLIC_WALLET_CONNECT_PROJECT_ID=your_walletconnect_id  # optional

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📁 Project Structure

blockmsg/
├── packages/
│   ├── fhevm-hardhat-template/    # Smart contracts & deployment
│   ├── fhevm-sdk/                 # FHEVM SDK package
│   └── nextjs/                    # React frontend application
├── docs/                          # Mintlify documentation
└── scripts/                       # Build and deployment scripts

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📚 Documentation

Full documentation available at docs.blockmsg.xyz

• Quickstart – Get started in 5 minutes
• How It Works – Learn about FHE encryption
• Privacy Architecture – Understand our zero-knowledge design
• Self-Destruct Messages – Time-based message destruction
• Developer Guide – Build on blockmsg

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🔗 Links

Resource	Link
🌐 Live App	blockmsg.xyz
📖 Documentation	docs.blockmsg.xyz
🐦 Twitter	@Gutslab
🔒 Zama FHE	zama.ai
📄 fhEVM Docs	docs.zama.ai

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🏆 Built With

Powered by Zama – Fully Homomorphic Encryption for Web3

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⚠️ Disclaimer

This software is experimental and unaudited. The smart contracts have NOT been formally audited by a third-party security firm. Use at your own risk.

By using blockmsg, you acknowledge that:

• Smart contracts may contain bugs or vulnerabilities
• You are solely responsible for your wallet security
• This is beta software deployed on testnet (Sepolia)
• No guarantees are made regarding the security or reliability of the protocol

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📄 License

This project is licensed under the BSD-3-Clause-Clear License. See the LICENSE file for details.

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🔐 Your messages. Your keys. Your privacy.