Garbled circuits for multi-input boolean functions
Multiparty computation is an area of cryptography which provides methods that two or more parties may use in order to jointly compute a function while keeping their inputs private. Garbled circuits, attributed to Andrew C. Yao, is a cryptographic technique used in secure multiparty computation. Any...
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| Summary: | Multiparty computation is an area of cryptography which provides methods that two or more parties may use in order to jointly compute a function while keeping their inputs private. Garbled circuits, attributed to Andrew C. Yao, is a cryptographic technique used in secure multiparty computation. Any function can be represented into a garbled boolean circuit and, with the help of Oblivious Transfer, a protocol can be built which allows parties to securely evaluate a function without exposing their inputs.
The naive implementation of Yao's Garbled Circuit Protocol is impractical for complex functions. Researchers come up with methods that aim to reduce the communication overhead and computational complexity of the protocol. Nowadays, cryptographic operations are supported by hardware and as a result the main bottleneck in garbling is considered to be communication.
This work introduces Yao's protocol and reviews several existent techniques which attempt to reduce the aforementioned costs, with a main focus on methods that aim to lessen the total number of ciphertexts needed to garble a function. Furthermore, it extends the recent and well established half gates method. Specifically, this work demonstrates that if half gates are combined and garbling is done on polynomials, then a 25% to 50% reduction in the amount of ciphertexts needed to garble portions of the circuit can be expected. |
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