Introduction to Secure Multi-Party Computation

Secure Multi-Party Computation (MPC) is a subfield of cryptography that enables multiple parties to jointly compute a function over their inputs while keeping those inputs private. This revolutionary concept allows organizations to collaborate on data analysis without revealing their sensitive information.

The Privacy Paradox

In our data-driven world, we face a fundamental paradox:

Data utility: More data leads to better insights, predictions, and services
Privacy requirements: Legal, ethical, and business requirements demand data protection

Secure computation technologies bridge this gap by enabling “privacy-preserving computation” - the ability to compute on encrypted data without decrypting it.

Key Concepts

What is Secure Multi-Party Computation?

MPC allows multiple parties to compute a joint function f(x₁, x₂, …, xₙ) where each party i holds a private input xᵢ. The computation reveals only the output of the function, not the individual inputs.

Security Properties

A secure MPC protocol guarantees:

Privacy: No party learns anything beyond what can be inferred from the output
Correctness: The computed result is accurate
Input independence: Parties must choose inputs before learning others’ inputs
Guaranteed output delivery: Honest parties receive the correct output