Farhad Taheri Ardakani; Siavash Bayat Sarmadi
Abstract
Secure multi-party computation (MPC) allows a group of parties to compute a function on their private inputs securely. Classic MPC protocols for two parties use either Yao's garbled circuit (GC) or the Goldreich-Micali-Wigderson (GMW) protocol. In this paper, we propose MISC, a multi-input secure computation ...
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Secure multi-party computation (MPC) allows a group of parties to compute a function on their private inputs securely. Classic MPC protocols for two parties use either Yao's garbled circuit (GC) or the Goldreich-Micali-Wigderson (GMW) protocol. In this paper, we propose MISC, a multi-input secure computation protocol, by combining GC and GMW in a novel way. MISC can evaluate multi-input AND gates, which can reduce the round complexity. Moreover, MISC reduces the communication overhead by 1.7x and 2.4x for 2-input and by 2x and 2.8x for 4-input AND gates compared to the state-of-the-art GMW-style and GC-style protocols, respectively. In order to use the MISC efficiently in different applications, we redesign common building block with multi-input AND gates such as Equality checking, Maxpool, Comparison, and Argmax/Argmin. Results on privacy-preserving applications, e.g., circuit-based private set intersection (PSI) and private machine learning (CNN inference) show that compared to GMW, MISC improves the total communication overhead by 3x and the total run time by 1.5x.
Maryam Rezaei Kashi; Mojtaba Bahramian
Abstract
Oblivious transfer is one of the important tools in cryptography, in which a sender sends a message to a receiver with a probability between 0 and 1, while the sender remains oblivious that the receiver has received the message.A flavor of $OT$ schemes is chosen $t$-out-of-$k$ ...
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Oblivious transfer is one of the important tools in cryptography, in which a sender sends a message to a receiver with a probability between 0 and 1, while the sender remains oblivious that the receiver has received the message.A flavor of $OT$ schemes is chosen $t$-out-of-$k$ oblivious transfer ($OT^t_k$). In an $OT^t_k$ scheme, a sender transfers $k$ messages to a receiver, the receiver can learn only $t$ of them, and the sender remains oblivious to which secrets are extracted by the receiver. In this paper, we first propose a type of Diffie-Hellman key exchange protocol using the generalized Jacobian of elliptic curves. Next, we introduce simple, secure two-round algorithms for $OT$, $OT^1_2$, $OT^t_k$.The security of proposed protocols is based on the intractability assumption of solving discrete logarithm problem; furthermore, in our $OT$ schemes, it is not necessary to map the messages to the points on the elliptic curve.