Securing a wireless communication has generally a vital importance, particularly when this communication is in a hostile environment like in wireless sensor networks (WSNs). The problem is how to create cryptographic keys between sensor nodes to ensure secure communications. Limited resources of sensor nodes make a public key cryptosystem such as RSA not feasible. So, most solutions rely on a s...

In this short paper, we describe a solution to protect users’ privacy in online social networks (OSNs). The solution achieves the following functionalities: (1) it enables users to store their private data securely; (2) it enables users, from the same or different OSNs, to compute their similarity through a secure protocol; (3) it enables similar users to establish a session key for secure comm...

Threshold public-key encryption (TPKE) allows a set of users to decrypt a ciphertext if a given threshold of authorized users cooperate. Existing TPKE schemes suffer from either long ciphertexts with size linear in the number of authorized users or can only achieve non-adaptive security. A non-adaptive attacker is assumed to disclose her target attacking set of users even before the system para...

There is a great deal of confusion in the cryptology literature relating to various identity related issues. By “names” (lower case), we are referring to informal, personal ways that we indicate others; by “NAMES” (upper case) we are referring to official ways that we use to indicate others. Both of these concepts are often confused with “identity”, which is something else altogether, and with ...

The purpose of key management is to provide procedures for handling cryptographic keying material to be used in symmetric or asymmetric cryptographic mechanisms. As a result of varied design decisions appropriate to different conditions, a large variety of key distribution protocols exist. There is a need tu explicate key distribution protocols in a way that allows to understand which results t...

In this paper we provide an analytical survey on security issues that are relevant for group key exchange protocols. We start with the description of the security requirements that have been informally described in the literature and widely used to analyze security of earlier group key exchange protocols. Most of these definitions were originally stated for two-party protocols and then adapted ...

Wireless Sensor Networks are prone to many security attacks. The most complex among them is the node compromise attack. Networks enhanced with services like aggregation and security require a different intrusion detection mechanism than the generally used solutions and there is a possibility of a compromised node producing false intrusion detection alarms. Therefore we need suitable mechanisms ...

In mobile ad hoc networks (MANETs), the research on key management of identity-based scheme is attracting more and more attention. In this paper, we study on four types of identity-based schemes which resist key escrow problem at different degrees, and introduce several schemes for each type. Then, we give an overview of the characteristics of their key management, and made a summary of key gen...

At Eurocrypt'95, Desmedt suggested a scheme which allows individuals to encrypt in such a way that the receiver can be traced by an authority having additional information. This paper shows that the proposed scheme does not have the required properties, by devising three non-speciied protocols misleading the authority. We also discuss how to repair Desmedt's scheme, such that our attacks are no...

The ephemeral pairing problem requires two or more specific physical nodes in a wireless broadcast network, that do not yet know each other, to establish a short-term relationship between them. Such shortlived pairings occur, for example, when one pays at a check-out using a wireless wallet. This problem is equivalent to the ephemeral key exchange problem, where one needs to establish a high-en...