Full-resilient memory-optimum multi-party non-interactive key exchange

Multi-Party Non-Interactive Key Exchange (MP-NIKE) is a fundamental cryptographic primitive in which users register into a key generation centre and receive a public/private key pair each. After that, any subset of these users can compute a shared key without any interaction. Nowadays, IoT devices suffer from a high number and large size of messages exchanged in the Key Management Protocol (KMP). To overcome this, an MP-NIKE scheme can eliminate the airtime and latency of messages transferred between IoT devices. MP-NIKE schemes can be realized by using multilinear maps. There are several attempts for constructing multilinear maps based on indistinguishable obfuscation, lattices and the Chinese Remainder Theorem (CRT). Nevertheless, these schemes are inefficient in terms of computation cost and memory overhead. Besides, several attacks have been recently reported against CRT-based and lattice-based multilinear maps. There is only one modular exponentiation-based MP-NIKE scheme in the literature which has been claimed to be both secure and efficient. In this article, we present an attack on this scheme based on the Euclidean algorithm, in which two colluding users can obtain the shared key of any arbitrary subgroup of users. We also propose an efficient and secure MP-NIKE scheme. We show how our proposal is secure in the random oracle model assuming the hardness of the root extraction modulo a composite number

An Enhanced TBAHIBE-LBKQS Techniques for Privacy Preservation in Wireless Network

In recent days, providing security to the data stored in wireless network is an important and challenging task. For this purpose, several existing privacy preservation and encryption algorithms are proposed in the existing works. But, it has some drawbacks such as, high cost, required more amount of time for execution and low level security. In order to overcome all these drawbacks, this paper proposes a novel technique such as, Tiered Blind and Anonymous Hierarchical Identity Based Encryption (TBAHIBE) and Location Based Keyword Query Search (LBKQS) for providing privacy preservation to the data stored in wireless network environment. In this work, the privacy is provided to the packet data stored in the Electronic Health Record (EHR). It includes two modules such as, secure data storage and location based keyword query search. In the first module, the packet data of the egg and, receptor, doctor and lab technician are stored in the encrypted format by using the proposed TBAHIBE technique. Here, the authenticated persons can view the packet data, for instance, the doctor can view the donor and receptor packet details. In the second module, the location based search is enabled based on the keyword and query. Here, the doctor, patient and other users can fetch the packet details in a filtered format. The main advantage of this paper is, it provides high privacy to the packet data in a secured way. The experimental results evaluate the performance of the proposed system in terms of computation cost, communication cost, query evaluation, encryption time, decryption time and key generation time

Critical Perspectives on Provable Security: Fifteen Years of Another Look Papers

We give an overview of our critiques of “proofs” of security and a guide to our papers on the subject that have appeared over the past decade and a half. We also provide numerous additional examples and a few updates and errata

Practical Witness Encryption for Algebraic Languages Or How to Encrypt Under Groth-Sahai Proofs

Witness encryption (WE) is a recent powerful encryption paradigm, which allows to encrypt a message using the description of a hard problem (a word in an NP-language) and someone who knows a solution to this problem (a witness) is able to efficiently decrypt the ciphertext. Recent work thereby focuses on constructing WE for NP complete languages (and thus NP). While this rich expressiveness allows flexibility w.r.t. applications, it makes existing instantiations impractical. Thus, it is interesting to study practical variants of WE schemes for subsets of NP that are still expressive enough for many cryptographic applications. We show that such WE schemes can be generically constructed from smooth projective hash functions (SPHFs). In terms of concrete instantiations of SPHFs (and thus WE), we target languages of statements proven in the popular Groth-Sahai (GS) non-interactive witness-indistinguishable/zero-knowledge proof framework. This allows us to provide a novel way to encrypt. In particular, encryption is with respect to a GS proof and efficient decryption can only be done by the respective prover. The so obtained constructions are entirely practical. To illustrate our techniques, we apply them in context of privacy-preserving exchange of information