Garbled Quantum Computation

Abstract: The universal blind quantum computation protocol (UBQC) (Broadbent, Fitzsimons, Kashefi 2009) enables an almost classical client to delegate a quantum computation to an untrusted quantum server (in form of a garbled quantum computation) while the security for the client is unconditional. In this contribution we explore the possibility of extending the verifiable UBQC (Fitzsimons, Kashefi 2012), to achieve further functionalities as was done for classical garbled computation. First, exploring the asymmetric nature of UBQC (client preparing only single qubits, while the server runs the entire quantum computation), we present a "Yao" type protocol for secure two party quantum computation. Similar to the classical setting (Yao 1986) our quantum Yao protocol is secure against a specious (quantum honest-but-curious) garbler, but in our case, against a (fully) malicious evaluator. Unlike the protocol in (Dupuis, Nielsen, Salvail 2010), we do not require any online-quantum communication between the garbler and the evaluator and thus no extra cryptographic primitive. This feature will allow us to construct a simple universal one-time compiler for any quantum computation using one-time memory, in a similar way with the classical work of (Goldwasser, Kalai, Rothblum 2008) while more efficiently than the previous work of (Broadbent, Gutoski, Stebila 2013).