Imagine that several spies decide to stop a common enemy together. To do this, they need to combine all the information they have, but none of them wants to share their secrets with the others.
We will help these poor fellows by building a system that allows computations to be performed in such a way that no extra information about the participants’ secrets is revealed.
In academic literature, this is called confidential computing, and in the real world it can be used, for example, to diagnose diseases using machine learning models trained on private patient data.