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Overview

Every message on blockmsg is encrypted using Fully Homomorphic Encryption (FHE) before being stored on the blockchain.
FHE is the gold standard for encryption - even quantum computers cannot break it.

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How Message Encryption Works

1

You Type a Message

You compose your message in the blockmsg interface
2

Client-Side Encryption

Your browser encrypts the message using FHE before it leaves your device
3

On-Chain Storage

The encrypted message is stored on the blockchain as a transaction
4

Recipient Decrypts

Only the recipient with their wallet private key can decrypt and read the message

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Technical Details

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Encryption Process

// Message is chunked into 32-bit segments
const chunks = chunkMessage(message, 4); // 4 bytes per chunk

// Each chunk is encrypted using TFHE
const encryptedHandles = chunks.map(chunk => 
  fhevmInstance.encrypt32(chunk)
);

// Encrypted handles are sent to the smart contract
await contract.sendDirectMessage(recipient, encryptedHandles);

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Decryption Process

  1. User requests decryption by clicking “Reveal Message”
  2. A cryptographic signature is generated using the wallet
  3. The fhEVM re-encrypts the data for the requesting user
  4. Client-side decryption reveals the plaintext message
Decryption requires an active wallet connection. Without your wallet, messages cannot be decrypted.

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Privacy Guarantees

FeatureGuarantee
Message ContentFully encrypted, unreadable without key
Sender AddressVisible on-chain (public blockchain)
Recipient AddressVisible on-chain (public blockchain)
TimestampVisible on-chain
Message LengthPartially hidden (chunked)
While message content is fully private, sender and recipient addresses are visible on the public blockchain.