Abstract Oblivious Transfer (
OT OT ) is a fundamental cryptographic primitive that becomes a crucial component of a practical secure protocol.
OT OT is typically implemented in software, and one way to accelerate its running time is by using hardware implementations. However, such implementations are vulnerable to side-channel attacks (SCAs). On the other hand, protecting interactive protocols against SCA is highly challenging due to their longer secrets (which include inputs and randomness), more complex design, and the need to run multiple instances. Consequently, there are no truly practical leakage-resistant
OT OT protocols yet. In this paper, we introduce two tailored indistinguishability-based security definitions for leakage-resilient
OT OT , focusing on protecting the sender’s state. Second, we propose a practical semi-honest secure
OT OT protocol that achieves these security levels while minimizing the assumptions on the protocol’s building blocks and the use of a secret state.
Abstract. We aim at constructing adaptive oblivious transfer protocols, enjoying fully simulatable security, from various well-known assumptions such as DDH, d-Linear, QR, DCR, and LWE. To this end, we present two generic constructions of adaptive OT, one of which utilizes verifiable shuffles together with threshold decryption schemes, while the other uses permutation networks together with what we call loosely-homomorphic key encapsulation schemes. We then show that specific choices of the building blocks lead to concrete adaptive OT protocols with fully simulatable security in the standard model under the targeted assumptions. Our generic methods can be extended to build universally composable (UC) secure, and leakage-resilient OT protocols.