Sub-second level MPC Network Ika: The Technical Game of FHE, TEE, ZKP and MPC

1. Overview and Positioning of the Ika Network

Ika Network is an innovative infrastructure based on multi-party secure computation (MPC) technology, with the most significant feature being sub-second response speed. Ika is highly compatible with the underlying design concepts of the Sui blockchain in terms of parallel processing and decentralized architecture, and will be directly integrated into the Sui development ecosystem in the future, providing plug-and-play cross-chain security modules for Sui Move smart contracts.

Ika is building a new type of security verification layer: serving as a dedicated signature protocol for the Sui ecosystem while also providing standardized cross-chain solutions for the entire industry. Its layered design balances protocol flexibility and development convenience, and it is expected to become an important practical case for the large-scale application of MPC technology in multi-chain scenarios.

1.1 Core Technology Analysis

The technical implementation of the Ika network revolves around high-performance distributed signatures. Its innovation lies in utilizing the 2PC-MPC threshold signature protocol in conjunction with Sui's parallel execution and DAG consensus, achieving true sub-second signing capabilities and large-scale decentralized node participation. Core functions include:

• 2PC-MPC Signature Protocol: The user's private key signing operation is decomposed into a process involving both the "User" and the "Ika Network" in a collaborative manner, using a broadcast model to maintain sub-second signature latency.

• Parallel Processing: Utilizing parallel computing to decompose a single signature operation into multiple concurrent subtasks, significantly enhancing speed by combining Sui's object parallel model.

• Large-scale node network: Supports thousands of nodes participating in signatures, with each node holding only a portion of the key shard, enhancing security.

• Cross-chain control and chain abstraction: Allows smart contracts on other chains to directly control accounts in the Ika network (dWallet) by deploying lightweight clients of the corresponding chain to achieve cross-chain operations.

1.2 The potential impact of Ika on the Sui ecosystem

• Expand cross-chain interoperability capabilities, supporting low-latency and high-security access to Sui network for on-chain assets such as Bitcoin and Ethereum.

• Provide a decentralized asset custody mechanism to enhance asset security.

• Simplify cross-chain interaction processes, allowing smart contracts on Sui to directly operate on accounts and assets of other chains.

• Provide a multi-party verification mechanism for AI automation applications to enhance the security and credibility of AI executing transactions.

1.3 Challenges faced by Ika

• Cross-chain interoperability standardization: It is necessary to attract more blockchains and projects to adopt it.

• MPC signature permission revocation issue: How to safely and efficiently replace nodes still poses potential risks.

• Dependence on the stability of the Sui network: Major upgrades to Sui may require Ika to make adaptations.

• Potential issues with the DAG consensus model: complexity in transaction ordering, consensus security, reliance on active users, etc.

II. Comparison of Projects Based on FHE, TEE, ZKP, or MPC

2.1 FHE

Zama & Concrete:

• General-purpose compiler based on MLIR
• Layered Bootstrapping Strategy
• Mixed encoding support
• Key packaging mechanism

Fhenix:

• Optimization for Ethereum EVM instruction set
• Ciphertext Virtual Register
• Off-chain oracle bridge module

2.2 TEE

Oasis Network:

• Layered Trusted Root Concept
• ParaTime interface uses Cap'n Proto binary serialization
• Durability Log Module

2.3 ZKP

Aztec:

• Noir Compilation
• Incremental Recursive Technology
• Parallelized Depth-First Search Algorithm
• Light Node Mode

2.4 MPC

Partisia Blockchain:

• Extension based on the SPDZ protocol
• Preprocessing Module
• gRPC communication, TLS 1.3 encrypted channel
• Dynamic Load Balancing

3. Privacy Computing: FHE, TEE, ZKP, and MPC

3.1 Overview of Different Privacy Computing Solutions

• Fully Homomorphic Encryption ( FHE ): Allows arbitrary computations to be performed on encrypted data, theoretically complete but with high computational overhead.

• Trusted Execution Environment ( TEE ): Relies on hardware trust roots, performance close to native computing, but has potential backdoor and side-channel risks.

• Multi-Party Secure Computation ( MPC ): No single point of trust hardware, but requires multiple party interactions, high communication overhead.

• Zero-Knowledge Proof ( ZKP ): Verifying the truth of a statement without revealing additional information

Adaptation scenarios of 3.2 FHE, TEE, ZKP and MPC

Cross-chain signature:

• MPC is suitable for multi-party collaboration and avoids single point private key exposure.
• TEE can run signature logic through SGX chips, which is fast but has hardware trust issues.
• FHE is relatively weak in signing scenarios.

DeFi scenarios:

• MPC is suitable for multi-signature wallets, vault insurance, and institutional custody.
• TEE is used for hardware wallet or cloud wallet services.
• FHE is mainly used to protect transaction details and contract logic.

AI and Data Privacy:

• The advantages of FHE are obvious, enabling fully encrypted computation.
• MPC is used for collaborative learning, but there are communication costs and synchronization issues.
• TEE can run models directly in a protected environment, but there are memory limitations and risks of side-channel attacks.

3.3 Differentiation of Different Solutions

Performance and Latency:

• FHE has a higher latency
• TEE minimum delay
• ZKP batch proof delay is controllable
• MPC delay is low to medium, greatly affected by network communication.

Trust Assumption:

• FHE and ZKP are based on mathematical problems and do not require trust in third parties.
• TEE relies on hardware and vendors
• MPC relies on a semi-honest or at most t-faulty model

Scalability:

• ZKP Rollup and MPC sharding support horizontal scaling
• FHE and TEE expansion need to consider computational resources and hardware node supply.

Integration Difficulty:

• TEE has the lowest entry threshold
• ZKP and FHE require specialized circuits and compilation processes
• MPC requires protocol stack integration and inter-node communication

4. Opinions on the Choice of Privacy Computing Technology

Different privacy computing technologies have their own advantages and disadvantages, and the choice should be based on specific application requirements and performance trade-offs. FHE, TEE, ZKP, and MPC all face the "performance, cost, security" impossible triangle issue when addressing practical use cases.

Future privacy computing solutions may be a complement and integration of multiple technologies, rather than a single technology that prevails. For example, Ika's MPC network provides decentralized asset control and can be combined with ZKP to verify the correctness of cross-chain interactions. Projects like Nillion are also beginning to integrate various privacy technologies to enhance overall capabilities.

The privacy computing ecosystem will tend to select the most suitable combination of technological components based on specific needs to build modular solutions.