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Dapp overview

The zero-knowledge proof (ZKP) dapp implements a privacy-preserving token system on Chromia that enables confidential transactions using the blockchain's built-in ZKP verification capabilities.

Dapp architecture​

The dapp is built using the Rell programming language and leverages Chromia's native ZKP infrastructure:

  • ZKPGTXModule: Built-in Chromia module for PLONK proof verification
  • FT4 integration: Seamless integration with Chromia's token standard
  • State management: On-chain tracking of commitments and nullifiers
  • Event logging: Encrypted note storage for wallet synchronization

ZKP integration on Chromia​

Transaction flow​

  1. Client submits transaction with zkp_plonk_verify operation
  2. ZKPGTXModule verifies the proof against stored verification keys
  3. Public signals extracted and passed to subsequent operations
  4. Dapp operations validate constraints and update state

Privacy model​

UTXO-based privacy​

  • Commitments: Private notes represented as Pedersen commitments
  • Nullifiers: Prevent double-spending without revealing note details

The dapp demonstrates how Chromia's built-in ZKP capabilities enable sophisticated privacy features directly at the blockchain protocol level, providing enterprise-grade confidential transactions with minimal complexity.