Multiparty Computation

Multiparty computation (MPC) is a technique in cryptography that enables multiple parties to jointly compute a function over their private inputs without revealing those inputs to each other or to any external parties. In other words, MPC allows multiple parties to perform a computation over their confidential data, without revealing any information about that data to others involved in the computation. This technique is particularly useful in scenarios where multiple parties need to collaborate and perform computations, but none of them want to share their data with the others, such as in financial transactions, healthcare data analysis, or voting protocols

How it Works

In an MPC protocol, two or more parties each hold a secret input, and they want to compute a function of their inputs without revealing their inputs to each other. The primary goal of an MPC protocol is to enable the participants to compute the desired computation results while preserving the privacy of their data.

For example, suppose that two hospitals want to collaborate to identify patients with a rare health condition without revealing their identities to each other. In that case, they can use MPC to jointly compute the proper function on their entire patient datasets. This approach can help them maintain privacy while still obtaining valuable insights into rare health conditions.

Benefits of MPC
  • Privacy Preservation: The primary advantage of MPC is privacy preservation. It allows parties to perform computations while keeping their inputs private, ensuring that sensitive information remains secure.
  • Increased Security: MPC increases security by eliminating the need for data to be centralized. Data is broken down into multiple pieces, and each piece is held by a different party. This reduces the risk of a successful data breach or cyberattack.
  • Trustless Collaboration: With MPC, parties can collaborate securely without having to trust one another.
Drawbacks of MPC
  • Complexity: MPC protocols can be complex to implement, and they require businesses or organizations looking to utilize MPC.
  • Latency: MPC computations can take longer to perform than other methods due to the need for parties to exchange information securely. This latency can be a significant issue in situations where time is of the essence.
  • Threshold Limitations: Some MPC protocols have a threshold limit on the number of participants involved in a computation. As more parties are involved, the protocol becomes more complicated and can increase the risk of a successful attack.

In summary, MPC has numerous benefits in terms of privacy, security, and trustless collaboration. However, implementing MPC can be challenging, and it may not be suitable for all use cases due to complexity, latency, and threshold limitations.