Skip to main content

CoFHE Architecture

Architecture

Click on the image to view in full size

System Overview​

CoFHE (Co-processor for Fully Homomorphic Encryption) is designed as a modular, layered architecture that enables privacy-preserving computations on blockchain networks. The system combines on-chain smart contracts with off-chain processing capabilities to deliver secure, efficient fully homomorphic encryption operations.

Key Components​

User-Facing Utilities​

  • Cofhejs: A TypeScript library that provides client-side functionality for encrypting inputs, managing permits, and decrypting outputs. Serves as the primary interface between applications and the CoFHE ecosystem.
  • FHE.sol: The Solidity library that enables smart contracts to perform operations on encrypted data. It exposes a comprehensive API for arithmetic, comparison, and logical operations on encrypted values.

Internal Utilities​

  • Task Manager: Acts as the gateway for all FHE operation requests, validating requests and managing permissions through the Access Control Layer (ACL).
  • Aggregator: Coordinates request queues and manages communication between on-chain contracts and the off-chain execution environment.
  • FHEOS Server: Executes the actual FHE operations on encrypted data and maintains the encrypted state.
  • Threshold Network: A distributed system that securely handles decryption requests through multi-party computation, ensuring no single entity can access the decryption key.
  • Ciphertext Registry: Maintains references to encrypted values and handles access control.

Data Flows​

CoFHE implements several critical data flows that maintain privacy throughout the computation lifecycle:

  1. Encryption Request: Manages the secure encryption of input data via ZK proofs before it enters the blockchain.
  2. FHE Operation Flow: Handles the process of requesting and executing computations on encrypted data.
  3. Decryption Request: Processes requests to decrypt data using the Threshold Network.
  4. Decrypt/Seal Output: Enables users to access encrypted results while maintaining privacy.

This architecture ensures that data remains encrypted throughout its entire lifecycle while still enabling complex computations, providing a foundation for privacy-preserving blockchain applications.