Private Computing with Garbled Circuits [Applications Corner]

Private computing provides a clever way to process data without revealing any details about the data itself to the party in charge of processing it. When the to-beprocessed data is a signal, private computing is customarily referred to as SPED, which stands for signal processing in the encrypted domain, since signal protection is usually achieved by encrypting the signals and processing them in encrypted form. Yao's garbled circuits (GCs) theory is one of the most used approaches to private computing. It permits the evaluation of binary circuits on input bits privately owned by the two parties involved in the computation, so that the final result is available to one of them (or both), while intermediate values cannot be discovered by any of the parties.The scope of this paper is to introduce the readers to GC's theory and provide some hints for its use in practical applications.