Four-round OT ⇒ Four-round MPC (Choudhuri–Ciampi–Goyal–Jain–Ostrovsky)

Standard model · CCG+20

Statement

If a four-round plain-model OT protocol exists that is secure against malicious adversaries with a black-box simulator running in expected polynomial time (four-round OT), every functionality has a four-round plain-model protocol that is secure with abort against a malicious adversary corrupting any number of parties and has a black-box simulator running in expected polynomial time (four-round MPC) — CCG+20.

Notes

• Four rounds are optimal: with a black-box proof of security, MPC in the plain model needs at least four rounds — GMPP16.
• For every $k\ge 5$, $k$-round MPC against any number of malicious parties follows from $k$-round malicious OT in the plain model — BL18.
• Polynomially hard DDH, QR or $N$-th residuosity also gives four-round MPC (DDH ⇒ four-round MPC) — BGJ+18.