Yao garbled circuit

Garbled circuit is a that enables two-party secure computation in which two mistrusting parties can jointly evaluate a function over their private inputs without the presence of a trusted third party. Andrew Yao of Stanford University first proposed the protocol in 1986 to solve his famous Millionaires' Problem. The protocol is also known as Yao's protocol, Yao's garbled circuit protocol or simply the GC protocol in the cryptography literature. In the garbled circuit protocol, the function has to be described as a Boolean circuit.

The problem discusses two millionaires, Alice and Bob, who are interested in knowing which of them is richer without revealing their actual wealth.

This problem is analogous to a more general problem where there are two numbers ${\displaystyle a}$ and ${\displaystyle b}$ and the goal is to solve the inequality ${\displaystyle a\geq b}$ without revealing the actual values of ${\displaystyle a}$ and ${\displaystyle b}$.

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