In 2003, Mu et al. proposed a non-interactive oblivious transfer scheme based on the standard ElGamal encryption scheme. Unfortunately, the receiver cannot verify the retrieved messages in the original scheme. Though they also proposed an extension to amend this drawback, this extension makes itself impracticable. On the other hand, the RSA cryptosystem is widely spread, and the certification infrastructure for it has been well built. As a result, we present two efficient non-interactive t-out-of-n oblivious transfer schemes in this paper, where one is for the honest receiver and the other is to inhibit the dishonest user from getting the valid signature of the sender. Moreover, the receiver can easily verify the requested messages in our schemes.
In 2003, Mu et al. proposed a non-interactive oblivious transfer scheme based on the standard ElGamal encryption scheme. Unfortunately, the receiver cannot verify the retrieved messages in the original scheme. Though they also proposed an extension to amend this drawback, this extension makes itself impracticable. On the other hand, the RSA cryptosystem is widely spread, and the certification infrastructure for it has been well built. As a result, we present two efficient non-interactive t-out-of-n oblivious transfer schemes in this paper, where one is for the honest receiver and the other is to inhibit the dishonest user from getting the valid signature of the sender. Moreover, the receiver can easily verify the requested messages in our schemes.
In a t-out-n oblivious transfer, the receiver can only receive t messages out of n messages sent by the sender; and the sender has no idea about which ones have been received. Majority of the existing of previous efficient oblivious transfer schemes require t calls of 1-out-n oblivious transfer to construct the t-out-n oblivious transfer. Its computational requirements and bandwidth consumption are quite demanding. Therefore, to guarantee the quality of electronic commercial service, an efficient t-out-n oblivious transfer scheme is urgently desired. Based on the RSA, we propose a new t-out-n oblivious transfer protocol for private information retrieval in this paper. In our method, only several modular multiplications and t hash functions are performed by a user (receiver) to obtain t messages. It is very suitable for the limited computation capacities of receivers such as smart cards or mobile units. Key words: Private information retrieval, security, RSA
A general approach for constructing t-out-n oblivious transfer is more practical than 1-out-n oblivious transfer for applications. To guarantee the quality of growing popular communication service, an efficient t-out-n oblivious transfer scheme is urgently desired. Based on the RSA and two-lock cryptosystem, we propose an efficient t-out-n oblivious transfer scheme in this paper. Compared with existing oblivious transfer schemes, our scheme can reduce many computations and communications for both the sender and the receiver. Moreover, our scheme is very suitable for smart-card users.
Oblivious transfer protocol,which is an important and useful cryptographic protocol,has been widely applied in cryptographic field,especially in construction of secure multi-party computation protocol.However,all of present oblivious transfer protocols have two drawbacks for requirement of their secrets: ① the receiver does not know whether message received is one of the messages held by the sender;② the sender does not know whether message received by the receiver is one of the messages designated by himself.In order to conquer these drawbacks,we firstly introduce the notion of verifiable oblivious transfer protocol,and firstly construct it by using proof protocol of knowledge,i.e.,∑-protocol,as main tool.
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.
Based on the RSA signature and (string) oblivious transfer, an enhanced oblivious transfer protocol is proposed which solves the access control problem for an oblivious transfer protocol. The protocol proposed has the property that only the receiver who has the signture issued by the central authority can open the message which he choose and that the sender can not decide whether the receiver has the signature or not. That is to say, the identity of the receiver can not be confirmed after the protocol. Under the decisional Diffie-Hellman assumption the proposed scheme has provable security.
Two novel constructions of one out of n oblivious transfer protocols from bilinear maps between groups are proposed. The protocols satisfy the category of non-interactive, mean that any sender S can obliviously transfer some secret(s) to a receiver R, but R does not send any messages back to S. The choice of a receiver is unconditionally secure. A sender's secrecy is guaranteed if the receiver is semi-honest in a standard model since the decision bilinear Diffie-Hellman problem is hard and the sender's secrecy is achieved when the receiver is a malicious party in a random oracle model since the bilinear Diffie-Hellman problem assumption holds. When a sender is a cheating party, the receiver will detect him/her and halt the protocol. A precise proof of the security of the protocols is presented.