FHE, ZK, and MPC: A Comparison of Three Encryption Technologies

In the field of encryption technology, Fully Homomorphic Encryption (FHE), Zero-Knowledge Proofs (ZK), and Multi-Party Computation (MPC) are three highly regarded technologies. Although they all aim to protect data privacy and security, there are significant differences in their specific application scenarios and technical complexities. Let's delve into the characteristics and applications of these three technologies.

Zero-Knowledge Proof (ZK): Proving without Revealing

Zero-knowledge proof technology allows one party (the prover) to prove the truth of a statement to another party (the verifier) without revealing any information other than the truth of the statement. This technology is particularly useful when it is necessary to verify permissions or identity.

For example, in the car rental scenario, customers can use their credit score to prove their creditworthiness to the car rental company without having to show detailed account statements. In the blockchain field, the anonymous coin Zcash uses ZK technology to achieve privacy protection of transactions.

Multi-Party Computation (MPC): Joint computation without leakage

MPC technology enables multiple participants to collaboratively perform computational tasks without requiring any party to disclose its input data. This is very useful in scenarios where data collaboration is needed while protecting the data privacy of all parties.

A simple example is calculating the average salary of multiple people: each person divides their salary into several parts and exchanges some data with others, ultimately obtaining the average value through aggregation, but without knowing the specific salaries of others.

In the cryptocurrency field, MPC technology is applied to develop wallet solutions with higher security. This type of wallet divides the private key into multiple parts, which are stored in different locations, enhancing the security of the assets.

Fully Homomorphic Encryption (FHE): Computation under Encryption

FHE technology allows computation on encryption data without the need for decryption. This enables users to delegate encrypted data to third parties for processing without revealing the original information.

In the fields of cloud computing and artificial intelligence, FHE technology can protect the security of sensitive data during processing. For example, medical records or personal financial information can be analyzed in an encryption state.

In the blockchain field, FHE technology can be used to improve the decentralization of PoS protocols. For example, the Mind Network project utilizes FHE technology to prevent plagiarism among nodes in small PoS networks, enhancing the security and decentralization of the network.

Technical Comparison

1. Application Focus:

   • ZK: Emphasizes how to prove the authenticity of information.
   • MPC: Focus on how multiple parties can securely compute together
   • FHE: Focused on how to perform computation in encryption state

2. Technical Complexity:

   • ZK: Requires deep mathematical and programming skills
   • MPC: Facing challenges in synchronization and communication efficiency
   • FHE: Computational efficiency is the main barrier.

3. Practical Applications:

   • ZK: Widely used in identity verification and privacy protection
   • MPC: Used for cross-institutional data analysis and secure wallets
   • FHE: Demonstrating potential in cloud computing and AI fields

The development of these encryption technologies is crucial for protecting data security and personal privacy. As the level of digitization continues to increase, their application in daily life will become more and more common, providing stronger security for our digital lives.