ZK Portal Chat

What It Is

Private messaging protocol powered by ZK-SNARKs. Every message is cryptographically authenticated through zero-knowledge proofs, encrypted end-to-end, and stored permanently on-chain. No accounts, no servers, no metadata leaks.

The Problem

Private communication on the internet relies on centralized infrastructure with:

• Server-side access to message content and metadata
• Single points of failure and censorship
• Identity systems controlled by corporations
• No cryptographic guarantees of sender authenticity

Existing encrypted messengers still require trust in a central operator. Blockchain messaging attempts exist but expose sender addresses and lack cryptographic privacy guarantees.

The Solution

Wallet-native messaging with zero-knowledge authentication:

• ZK-SNARK proofs
  • Cryptographically prove identity without exposing keys
• On-chain storage
  • Messages persist on Ethereum and Base, censorship-resistant
• Stealth addresses
  • Recipient identity obscured on-chain
• Wallet-derived keys
  • No passwords, no seed phrases to manage

How It Works

1. Connect wallet (Ethereum or Base)
2. Derive viewing key (one-time wallet signature)
3. Enter recipient wallet address
4. Compose and send message
5. ZK-SNARK proof generated in browser
6. Encrypted message posted on-chain with proof verification

No account creation. No server registration. Viewing keys deterministically derived from wallet signature - same key on any device.

Technical Architecture

Zero-Knowledge Layer

• Groth16 ZK-SNARKs for viewing key ownership proofs
• Poseidon hashing for ZK-optimized commitments and nullifiers
• Client-side proof generation via snarkjs in browser
• On-chain verification through deployed Verifier contracts

ZK Circuit

• Proves ownership of viewing key without revealing it
• Generates nullifiers to prevent replay attacks
• Creates commitments binding message to sender
• All computation happens client-side - keys never transmitted

Encryption Layer

• End-to-end encrypted message content
• EIP-5564 stealth addresses for recipient privacy
• Only intended recipient can decrypt

Storage Layer

• Encrypted messages stored on Ethereum and Base
• ZKNoteRegistry smart contract with proof verification
• Permanent, immutable message history
• No server infrastructure required

Key Management

• Viewing keys derived from wallet signatures
• Deterministic derivation - same key on any device with your wallet
• Keys never transmitted or stored remotely
• Sign once, decrypt forever

Features

Security Model

ZK Portal Chat is a client application. It does not operate servers, store messages, or custody keys.

What the system does NOT do:

• Does not store viewing keys or private keys
• Does not maintain message databases
• Does not relay messages through servers
• Does not collect metadata or analytics
• Does not require trust in any operator

What happens:

• All encryption/decryption happens locally in browser
• ZK-SNARK proofs generated client-side using snarkjs
• Messages posted directly to smart contract with proof
• On-chain Verifier confirms proof validity
• Only recipients with correct viewing key can decrypt

Privacy Guarantees

Deployed Contracts

Development Status