Space–time (ST) constellations that are linear over the field of complex numbers are considered. Relevant design criteria for these constellations are summarized and some fundamental limits to their achievable performances are established. The fundamental tradeoff between rate and diversity is investigated under different constraints on the peak power, receiver complexity, and rate scaling with...

Very recently, the concept of Traceable Identity-based Encryption (IBE) scheme (or Accountable Authority Identity based Encryption scheme) was introduced in Crypto 2007. This concept enables some mechanisms to reduce the trust of a private key generator (PKG) in an IBE system. The aim of this paper is threefold. First, we discuss some subtleties in the first traceable IBE scheme in the Crypto 2...

In this paper we propose a new anonymous password-based authenticated key exchange protocol. The communication cost of our protocol is sub-linear ( ), O N which improves a previous one of O(N) cost, where N is the number of users in the system. We show that the session key is secure against an active adversary in the random oracle model and identity anonymity is secure against a semi-honest adv...

Abstract: The paper presents a study of properties of ensemble averages of Wigner time-frequency distributions (WDs) of random processes defined by statistically independent samples of stationary and nonstationary Gaussian noise and of radio-frequency telecommunication signals. We used samples of PSK and FSK signals transmitting random telegraph signals. The WDs of single samples of these rando...

A one-time signature scheme using run-length encoding is presented, that in the random oracle model offers security against chosen-message attacks. For parameters of interest, the proposed scheme enables about 33% faster verification with a comparable signature size than a construction of Merkle and Winternitz. The public key size remains unchanged (1 hash value). The main price for the faster ...

We present a public key encryption primitive called A Posteriori Openable Public Key Encryption (APO-PKE). In addition to conventional properties of public key cryptosystems, our primitive allows each user, who has encrypted messages using different public keys, to create a special decryption key. A user can give this key to a judge to open all messages that have been encrypted in a chosen time...

A new fundamental and secure group key management approach with a group controller GC using the theory of polynomial functions over a vector space over finite field is developed, where each member in the group corresponds to a vector in the vector space and the GC computes a central vector, whose inner product with every member’s ID vector are identical. The central vector is published and each...

Securing e-health applications in the context of Internet of Things (IoT) is challenging. Indeed, resources scarcity in such environment hinders the implementation of existing standard based protocols. Among these protocols, MIKEY (Multimedia Internet KEYing) aims at establishing security credentials between two communicating entities. However, the existing MIKEY modes fail to meet IoT specific...