The Development and Application Prospects of Fully Homomorphic Encryption Technology

Cryptographic technology has always played a key role in the advancement of human civilization, especially in the fields of information security and privacy protection. It not only provides protection for data transmission and storage, but its asymmetric encryption and hash functions were creatively applied by Satoshi Nakamoto to design the proof-of-work mechanism of Bitcoin, ushering in the blockchain era.

With the development of blockchain technology, cutting-edge cryptographic techniques such as zero-knowledge proof, multiparty computation, and fully homomorphic encryption continue to emerge. Among them, fully homomorphic encryption ( FHE ) is particularly noteworthy, as it allows arbitrary computations on encrypted data without decryption, bringing new possibilities for privacy computing.

Introduction to FHE

FHE is a type of Homomorphic Encryption technology that allows computations on ciphertexts, and the results can be directly mapped to plaintext. Compared to partial homomorphic encryption, FHE supports an unlimited number of computations and operations.

Despite the complex mathematical principles of FHE, its usage process is relatively simple: generate a key pair, encrypt data, perform homomorphic computation, and decrypt the results. In practice, the management of the decryption key is crucial.

Implementation of FHE on Blockchain

To implement FHE on the blockchain, the ideal approach is to encapsulate it as a smart contract library. This requires the virtual machine to support the specific instruction set needed for FHE. Based on the widely used EVM, Zama has developed the fhEVM that supports the implementation of privacy computing in Solidity.

The core features of fhEVM include:

• Provides FHE operation support through precompiled contracts
• Decryption mechanism based on distributed threshold protocol
• Solidity contract library that lowers the development threshold

FHE-Rollups Solution

In order to build a complete ecosystem, Fhenix explores the combination of fhEVM and Rollup technology, proposing the FHE-Rollups type Layer 2 solution. Considering the implementation difficulty, Fhenix has chosen a technology route based on Optimistic Rollups.

The technology stack of Fhenix includes:

• Variant of Arbitrum Nitro's fraud prover
• Core Library fheOS
• Threshold Service Network ( TSN )

Fhenix also introduced the Relay module, allowing various blockchain networks to connect to FHE Coprocessors to utilize FHE functions.

The Application Prospects of FHE

FHE technology has shown great potential in multiple fields:

• Privacy-protected fully homomorphic encryption games
• DeFi/MEV protection
• Privacy protection during AI model training

FHE Ecosystem Development

In addition to Zama and Fhenix, there are a series of noteworthy projects in the FHE ecosystem:

• Sunscreen: self-developed FHE compiler
• Mind Network: FHE network combined with EigenLayer
• PADO Labs: zkFHE integrating ZKP and FHE
• Arcium: Parallel Confidential Computing Network
• Inco Network: Layer 1 that optimizes FHE computation efficiency
• Treat: FHE Layer3 of the Shiba ecosystem
• octra: Supports FHE networks with isolated execution environments
• BasedAI: A network that introduces FHE functionality for LLMs
• Encifher: Committed to the FHEML project
• Privasea: FHE network for AI field ML inference

FHE technology is rapidly developing and is expected to play an important role in multiple fields in the future, bringing new possibilities to blockchain.