Oblivious transfer (OT) is a significant primitive with wide use in secure two-party computation, private set intersection private and other cryptographic schemes. In the past ten years, different variants of OT primitive like cut-and-choose OT (CCOT) and outsourced OT (OOT), have been proposed so as to satisfy various emerging models. In this paper, we firstly propose and formalize a new primitive called permutable cut-and-choose OT (PCCOT) which generalizes the original CCOT functionality. Furthermore, we construct an efficient PCCOT protocol in the presence of malicious adversaries using the Decisional Diffie-Hellman (DDH) hard assumption. It is worth mentioning that we apply the PCCOT primitive to the efficient construction of secure wildcard pattern matching (WPM) protocol. The WPM functionality allows a party to determine the locations of its pattern with wildcard characters occurs in a long text of another party while revealing nothing to either party in addition to the length of their own inputs. Our proposed secure WPM protocol via PCCOT is secure against semi-honest adversary with 2 rounds and has identical communication cost as the the state-of-the-art scheme.
Oblivious transfer (OT) is a significant primitive with wide use in secure two-party computation, private set intersection private and other cryptographic schemes. In the past ten years, different variants of OT primitive like cut-and-choose OT (CCOT) and outsourced OT (OOT), have been proposed so as to satisfy various emerging models. In this paper, we firstly propose and formalize a new primitive called permutable cut-and-choose OT (PCCOT) which generalizes the original CCOT functionality. Furthermore, we construct an efficient PCCOT protocol in the presence of malicious adversaries using the Decisional Diffie-Hellman (DDH) hard assumption. It is worth mentioning that we apply the PCCOT primitive to the efficient construction of secure wildcard pattern matching (WPM) protocol. The WPM functionality allows a party to determine the locations of its pattern with wildcard characters occurs in a long text of another party while revealing nothing to either party in addition to the length of their own inputs. Our proposed secure WPM protocol via PCCOT is secure against semi-honest adversary with 2 rounds and has identical communication cost as the the state-of-the-art scheme.
In secure two-party computation protocols based on garbled circuit, oblivious transfer (OT) plays an important role in transferring the garbled keys of the participants. In addition to the traditional OT primitive, many other variants of OT have also been presented, such as outsourced oblivious transfer (OOT), cut-and-choose oblivious transfer (CCOT), cut-and-choose bilateral oblivious transfer (CCBOT), etc. These new primitives significantly improve the efficiency and feasibility of secure two-party computation protocols, mainly in optimising computational complexity and interactive rounds. Among these primitives, CCBOT proposed by Zhao et al. in TrustCom 2015 is a novel one and helps to minimize the round complexity of the outer secure two-party computation protocols. In addition, they constructed a CCBOT protocol based on homomorphic encryption scheme in the malicious model. However, their protocol uses the cut-and-choose technique to guarantee security against malicious adversaries, as a result the protocol has an error probability. The commitment scheme is also inevitably involved in their protocol. In this paper, we present a CCBOT protocol with the security against malicious adversaries based on the Decisional Diffie-Hellman (DDH) assumption. Our proposed protocol avoids using the cut-and-choose technique and commitment scheme. In terms of efficiency, our protocol is much more efficient than the previous protocol.
The Yao's protocol based on garbled circuits is the foundation of secure two-party computation protocols, and Oblivious Transfer (OT), as a important tool in modern cryptography, plays a crucial role in transmitting garbled keys in the Yao's protocol. In the past decades, considerable attentions have been paid to the Cut-and-Choose technique which is applied to OT protocols to prevent malicious P1(called circuit generator) from constructing wrong garbled circuits. Additionally, Bilateral OT becomes a focus point, which can simultaneously transmit P1's and P2's (called circuit evaluator) garbled keys to guarantee input consistency of two parties and improve transmission efficiency. As can be seen, some Cut-and-Choose Bilateral OT (CCBOT) protocols have been proposed. Since CCBOT has emerged, the probability of malicious P1constructing wrong garbled circuits without being found becomes lower and the input consistency problem is properly resolved too. However, the security of most CCBOT protocols are facing challenges since they are based on the Decisional Diffie-Hellman (DDH) assumption, Quadratic Residues (QR) assumption and Decisional Composite Residuosity (DCR) assumption. In this paper, we present a novel CCBOT protocol with the security against malicious adversaries based on the Computational Diffie-Hellman (CDH) assumption, and analysize the correctness, efficiency and security of the constructed protocol. Besides, we analysize the cheating probability of P1in the CCBOT and extend the CCBOT to Single-Choice CCBOT to make the protocol more applicable.
We propose postquantum universal composable (UC) cut-and-choose oblivious transfer (CCOT) protocol under the malicious adversary model. In secure two-party computation, we construct s copies’ garbled circuits, including half check circuit and half evaluation circuit. The sender can transfer the key to the receiver by CCOT protocol. Compared to PVW-OT [6] framework, we invoke WQ-OT [35] framework with reusability of common random string ( crs ) and better security. Relying on LWE’s assumption and the property of the Rounding function, we construct an UC-CCOT protocol, which can resist quantum attack in secure two-party computation.
Oblivious transfer is a fundamental tool in cryptographic protocols, especially in secure two-party computation. In TCC 2011, Lindell and Pinkas proposed a variant called cut-and-choose oblivious transfer, which did a great job in solving the selective failure attack in secure two-party computation protocols based on cut-and-choose paradigm. In this paper, we present a new primitive called cut-and-choose bilateral oblivious transfer. As an extension to cut-and-choose oblivious transfer, in addition to overcoming the selective failure attack, this primitive also makes a contribution to reducing the round number of the protocols that invoke it. This is very important in the scenarios where interactions between parties are limited. Besides, the application of this primitive in the outer protocols enables us to present a more modular and clean high-level description of the protocol framework. Furthermore, we believe that the new primitive is of independent research interest itself and could be useful in many cut-and-choose scenarios. Based on homomorphic encryption, we construct an efficient instantiation of this primitive in malicious model, and present a formal rigorous proof of its security under ideal/real simulation paradigm.
Oblivious transfer is a fundamental tool in cryptographic protocols, especially in secure two-party computation. In TCC 2011, Lindell and Pinkas proposed a variant called cut-and-choose oblivious transfer, which did a great job in solving the selective failure attack in secure two-party computation protocols based on cut-and-choose paradigm. In this paper, we present a new primitive called cut-and-choose bilateral oblivious transfer. As an extension to cut-and-choose oblivious transfer, in addition to overcoming the selective failure attack, this primitive also makes a contribution to reducing the round number of the protocols that invoke it. This is very important in the scenarios where interactions between parties are limited. Besides, the application of this primitive in the outer protocols enables us to present a more modular and clean high-level description of the protocol framework. Furthermore, we believe that the new primitive is of independent research interest itself and could be useful in many cut-and-choose scenarios. Based on homomorphic encryption, we construct an efficient instantiation of this primitive in malicious model, and present a formal rigorous proof of its security under ideal/real simulation paradigm.
Oblivious transfer is a fundamental tool in modern cryptography. It plays an important role in the research of security protocols. In recent years, many oblivious transfer variants with more powerful functionalities are proposed, so as to be fit in different kinds of requirements and scenarios. In this paper, a new oblivious transfer variant, called cut-and-choose bilateral oblivious transfer, is proposed. Based on homomorphic encryption, an efficient one-round protocol of this primitive is constructed, accompanied with rigorous security proof in semi-honest model. When applied in security protocols based on cut-and-choose technique (especially in secure two-party computation), cut-and-choose bilateral oblivious transfer enables a more modular high-level description of the protocol framework, as well as reduces the round complexity of the protocols. Besides, as a basic tool in the information security area, this primitive itself is of independent research interest.