> ## Documentation Index > Fetch the complete documentation index at: https://cofhe-docs.fhenix.zone/llms.txt > Use this file to discover all available pages before exploring further. # CoFHE Architecture Overview > Comprehensive overview of the CoFHE architecture, components, and data flows for privacy-preserving blockchain computations # CoFHE Architecture CoFHE Architecture Diagram *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 * **Client SDK** (`@cofhe/sdk`): 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). * **Slim Listener**: Monitors blockchain events and forwards FHE operation requests to the off-chain execution environment. * **Result Processor**: Handles FHE operation results from the computation layer and publishes them back to the blockchain. * **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.