## Cryptology ePrint Archive: Report 2020/1464

Round Efficient Secure Multiparty Quantum Computation with Identifiable Abort

Bar Alon and Hao Chung and Kai-Min Chung and Mi-Ying Huang and Yi Lee and Yu-Ching Shen

Abstract: A recent result by Dulek et al. (EUROCRYPT 2020) showed a secure protocol for computing any quantum circuit even without the presence of an honest majority. Their protocol, however, is susceptible to a denial of service'' attack and allows even a single corrupted party to force an abort. We propose the first quantum protocol that admits security-with-identifiable-abort, which allows the honest parties to agree on the identity of a corrupted party in case of an abort. Additionally, our protocol is the first to have the property that the number of rounds where quantum communication is required is independent of the circuit complexity. Furthermore, if there exists a post-quantum secure classical protocol whose round complexity is independent of the circuit complexity, then our protocol has this property as well. Our protocol is secure under the assumption that classical fully homomorphic encryptions schemes exist.

Category / Keywords: cryptographic protocols / quantum cryptography