The rapid development of digital data sharing has made information security a crucial concern in communication. system heavily relies on encryption methods. These algorithms employ strategies to increase secrecy and privacy by obscuring the information, which only those parties who have accompanying key can decode or decrypt. Nevertheless, these methods also use lot computational resources, inc...

This paper addresses the problem of information protection in hierarchical groups. Higher level groups of participants can control the information ow (the decryption ability) to lower level groups. If a higher level group decides to allow a lower level group to read the message, it passes a go ahead ticket so the lower level group can decrypt the cryptogram and read the message. The formal mode...

In this paper, we propose an efficient protocol for proving the correctness of shuffling and an efficient protocol for simultaneously proving the correctness of both shuffling and decryption. The former protocol is the most efficient in computational and communication complexity among 3-move honest verifier perfect zero-knowledge protocols for proving a shuffling of ElGamal cipher-texts. The la...

In this paper, we propose a construction of fair and efficient mutual Private Set Intersection (mPSI) with linear communication and computation complexities, where the underlying group is of prime order. The main tools in our approach include: (i) ElGamal and Distributed ElGamal Cryptosystems as multiplicatively Homomorphic encryptions, (ii) Cramer-Shoup Cryptosystem as Verifiable encryption. O...

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In this paper, we propose a generic construction of chosen-ciphertext secure cryptosystems against adversaries with a bounded number of decrytion queries from arbitrary semantically secure encryption in a black box manner. Our construction is not only an alternative to the previously known technique, i.e. the Naor-Yung paradigm [37, 19, 42], but also has some interesting properties. Especially,...

The MOR cryptosystem is a generalization of the ElGamal cryptosystem, where the discrete logarithm problem works in the automorphism group of a group G, instead of the group G itself. The framework for the MOR cryptosystem was first proposed by Paeng et al. [13]. Mahalanobis [10] used the group of unitriangular matrices for the MOR cryptosystem. That effort was successful: the MOR cryptosystem ...

At CRYPTO 2016, Couteau, Peters and Pointcheval introduced a new primitive called encryption switching protocols, allowing to switch ciphertexts between two encryption schemes. If such an ESP is built with two schemes that are respectively additively and multiplicatively homomorphic, it naturally gives rise to a secure 2-party computation protocol. It is thus perfectly suited for evaluating fun...