yao.md

title	Yao protocol
parent	Protocols
has_children	true
nav_order	2

Yao Protocol

The protocol consists of 6 steps as follows:

1. The underlying function (e.g., in the millionaires' problem, comparison function) is described as a Boolean circuit with 2-input gates. The circuit is known to both parties. This step can be done beforehand by a third-party.

2. Alice garbles (encrypts) the circuit. We call Alice the garbler.

3. Alice sends the garbled circuit to Bob along with her encrypted input.

4. Bob through oblivious transfer receives Alice's encrypted circuit and input. In terms of the definition from above, Bob is the receiver and Alice the sender at this oblivious transfer.

5. Bob evaluates (decrypts) the circuit and obtains the encrypted outputs. We call Bob the evaluator.

6. Alice and Bob communicate to learn the output.