TY - GEN
T1 - Secure multiparty computation with minimal interaction
AU - Ishai, Yuval
AU - Kushilevitz, Eyal
AU - Paskin, Anat
PY - 2010
Y1 - 2010
N2 - We revisit the question of secure multiparty computation (MPC) with two rounds of interaction. It was previously shown by Gennaro et al. (Crypto 2002) that 3 or more communication rounds are necessary for general MPC protocols with guaranteed output delivery, assuming that there may be t ≥ 2 corrupted parties. This negative result holds regardless of the total number of parties, even if broadcast is allowed in each round, and even if only fairness is required. We complement this negative result by presenting matching positive results. Our first main result is that if only one party may be corrupted, then n ≥ 5 parties can securely compute any function of their inputs using only two rounds of interaction over secure point-to-point channels (without broadcast or any additional setup). The protocol makes a black-box use of a pseudorandom generator, or alternatively can offer unconditional security for functionalities in NC1. We also prove a similar result in a client-server setting, where there are m ≥ 2 clients who hold inputs and should receive outputs, and n additional servers with no inputs and outputs. For this setting, we obtain a general MPC protocol which requires a single message from each client to each server, followed by a single message from each server to each client. The protocol is secure against a single corrupted client and against coalitions of t1 (which is implied by standard cryptographic assumptions), or alternatively can offer unconditional security for functionalities in NC1.
AB - We revisit the question of secure multiparty computation (MPC) with two rounds of interaction. It was previously shown by Gennaro et al. (Crypto 2002) that 3 or more communication rounds are necessary for general MPC protocols with guaranteed output delivery, assuming that there may be t ≥ 2 corrupted parties. This negative result holds regardless of the total number of parties, even if broadcast is allowed in each round, and even if only fairness is required. We complement this negative result by presenting matching positive results. Our first main result is that if only one party may be corrupted, then n ≥ 5 parties can securely compute any function of their inputs using only two rounds of interaction over secure point-to-point channels (without broadcast or any additional setup). The protocol makes a black-box use of a pseudorandom generator, or alternatively can offer unconditional security for functionalities in NC1. We also prove a similar result in a client-server setting, where there are m ≥ 2 clients who hold inputs and should receive outputs, and n additional servers with no inputs and outputs. For this setting, we obtain a general MPC protocol which requires a single message from each client to each server, followed by a single message from each server to each client. The protocol is secure against a single corrupted client and against coalitions of t1 (which is implied by standard cryptographic assumptions), or alternatively can offer unconditional security for functionalities in NC1.
KW - Secure multiparty computation
KW - round complexity
UR - http://www.scopus.com/inward/record.url?scp=77956991013&partnerID=8YFLogxK
U2 - 10.1007/978-3-642-14623-7_31
DO - 10.1007/978-3-642-14623-7_31
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AN - SCOPUS:77956991013
SN - 3642146228
SN - 9783642146220
T3 - Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
SP - 577
EP - 594
BT - Advances in Cryptology - CRYPTO 2010 - 30th Annual Cryptology Conference, Proceedings
T2 - 30th Annual International Cryptology Conference, CRYPTO 2010
Y2 - 15 August 2010 through 19 August 2010
ER -