Oblivious transfer is a type of message transfer in which a sender transmits one out of many potential pieces of information to the receiver, but she has no knowledge about the actual piece of information being received by the receiver. Oblivious transfer is a deceptively simple scheme that has many possible applications such as secure multiparty computation, private set intersection, federated learning, zero-knowledge proofs, accessing sensitive data etc. Security of most classical oblivious transfer protocols is based upon the unproven assumptions about the computational complexity of certain number theoretic problems such as integer factorization. So, existing classical protocols for oblivious transfer are only computationally secure and not unconditionally secure. Although many quantum oblivious protocols have been proposed lately, they are not simple and easy to implement. In the present work we propose a quantum oblivious transfer protocol that is efficient, simple and easily implementable with the existing quantum technology.
Oblivious transfer is a type of message transfer in which a sender transmits one out of many potential pieces of information to the receiver, but she has no knowledge about the actual piece of information being received by the receiver. Oblivious transfer is a deceptively simple scheme that has many possible applications such as secure multiparty computation, private set intersection, federated learning, zero-knowledge proofs, accessing sensitive data etc. Security of most classical oblivious transfer protocols is based upon the unproven assumptions about the computational complexity of certain number theoretic problems such as integer factorization. So, existing classical protocols for oblivious transfer are only computationally secure and not unconditionally secure. Although many quantum oblivious protocols have been proposed lately, they are not simple and easy to implement. In the present work we propose a quantum oblivious transfer protocol that is efficient, simple and easily implementable with the existing quantum technology.
Abstract Oblivious transfer is a type of message transfer in which a sender transmits one out of many potential pieces of information to the receiver, but she has no knowledge about the actual piece of information being received by the receiver. Oblivious transfer is a deceptively simple scheme that has many possible applications such as secure multiparty computation, private set intersection, federated learning, zero-knowledge proofs, accessing sensitive data etc. Security of most classical oblivious transfer protocols is based upon the unproven assumptions about the computational complexity of certain number theoretic problems such as integer factorization. So, existing classical protocols for oblivious transfer are only computationally secure and not unconditionally secure. Although many quantum oblivious protocols have been proposed lately, they are not simple and easy to implement. In the present work we propose a quantum oblivious transfer protocol that is efficient, simple and easily implementable with the existing quantum technology.
Oblivious transfer protocol is a basic building block in cryptography and is used to transfer information from a sender to a receiver in such a way that, at the end of the protocol, the sender does not know if the receiver got the message or not. Since Shor's quantum algorithm appeared, the security of most of the classical cryptographic schemes has been compromised, as they rely on the fact that factoring is infeasible. To overcome this, quantum mechanics has been used intensively in the past decades, and alternatives resistant to quantum attacks have been developed in order to fulfill the (potential) lack of security of a significant number of classical schemes. In this paper, we present a quantum computationally secure protocol for bit-string oblivious transfer between two parties, under the assumption of quantum hardness of state distinguishability and the constraint of performing at most few-qubit measurements (leaving open the question of general attacks performed on all qubits involved). The protocol is feasible, in the sense that it is implementable in polynomial time.
Oblivious transfer (OT) protocol is an essential tool in cryptography that provides a wide range of applications such as secure multi-party computation, private information retrieval, private set intersection, contract signing, and privacy-preserving location-based services. The OT protocol has different variants such as one-out-of-2, one-out-of- n , k -out-of- n , and OT extension. In the OT (one-out-of-2, one-out-of- n , and OT extension) protocol, the sender has a set of messages, whereas the receiver has a key. The receiver sends that key to the sender in a secure way; the sender cannot get any information about the received key. The sender encrypts every message by operating on every message using the received key and sends all the encrypted messages to the receiver. The receiver is able to extract only the required message using his key. However, in the k -out-of- n OT protocol, the receiver sends a set of k keys to the sender, and in replay, the sender sends all the encrypted messages. The receiver uses his keys and extracts the required messages, but it cannot gain any information about the messages that it has not requested. Generally, the OT protocol requires high communication and computation cost if we transfer millions of oblivious messages. The OT extension protocol provides a solution for this, where the receiver transfers a set of keys to the sender by executing a few numbers of OT protocols. Then, the sender encrypts all the messages using cheap symmetric key cryptography with the help of a received set of keys and transfers millions of oblivious messages to the receiver. In this work, we present different variants of OT protocols such as one-out-of-2, one-out-of- n , k -out-of- n , and OT extension. Furthermore, we cover various aspects of theoretical security guarantees such as semi-honest and malicious adversaries, universally composable, used techniques, computation, and communication efficiency aspects. From the analysis, we found that the semi-honest adversary-based OT protocols required low communication and computation costs as compared to malicious adversary-based OT protocols.
Oblivious transfer, first introduced by Rabin, is one of the basic building blocks of cryp-tographic protocols. In an oblivious transfer (or more exactly, in its 1-out-of-2 variant), one party known as the sender has a pair of messages and the other party known as the receiver obtains one of them. Somewhat paradoxically, the receiver obtains exactly one of the messages (and learns nothing of the other), and the sender does not know which of the messages the receiver obtained. Due to its importance as a building block for secure protocols, the efficiency of oblivious transfer protocols has been extensively studied. However, to date, there are almost no known oblivious transfer protocols that are secure in the presence of malicious adversaries under the real/ideal model simulation paradigm (without using general zero-knowledge proofs). Thus, efficient protocols that reach this level of security are of great interest. In this paper we present efficient oblivious transfer protocols that are secure according to the ideal/real model simulation paradigm. We achieve constructions under the DDH, Nth residuosity and quadratic residuosity assumptions, as well as under the assumption that homomorphic encryption exists. 1
Oblivious transfer is a fundamental cryptographic primitive that is useful for secure multiparty computation. There are several variants of oblivious transfer. We consider 1-out-of-2 oblivious transfer, where a sender sends two bits of information to a receiver. The receiver receives only one of the two bits, while the sender does not know which bit the receiver has received. Perfect quantum oblivious transfer with information-theoretic security is known to be impossible. We aim to find the lowest possible cheating probabilities. Bounds on cheating probabilities have been investigated for “complete” protocols, where if both parties follow the protocol, the bit value obtained by the receiver matches the sender's bit value. We instead investigate incomplete protocols, where the receiver obtains an incorrect bit value with probability p f . We present optimal noninteractive protocols where Alice's bit values are encoded in four symmetric pure quantum states, and where she cannot cheat better than with a random guess. We find the protocols such that for a given p f , Bob's cheating probability p r is as low as possible, and vice versa. Furthermore, we show that noninteractive quantum protocols can outperform noninteractive classical protocols and give a lower bound on Bob's cheating probability in interactive quantum protocols. Importantly for optical implementations, our protocols do not require entanglement nor quantum memory.
Abstract Oblivious transfer (OT) protocol is an essential building block for secure multiparty computation. The transmission of quantum messages is conductive in executing complex secure multiparty quantum computation tasks and even distributed quantum computation tasks. However, as an important form of OT protocol, existing all‐or‐nothing OT protocols only work for the transmission of classical messages thus limiting application scenarios. To tackle this issue, a counterfactual all‐or‐nothing OT protocol is proposed for quantum messages. Compared with existing all‐or‐nothing OT protocols for classical messages, the proposed protocol has three advantages: i) it is achieved without any physical particles traveling between the sender and the receiver thus reducing the communication complexity; ii) no prior entanglement between the sender and the receiver is required thus facilitating protocol implementation, and iii) it works for known even unknown quantum messages thereby offering broader application scenarios.