Mostly, current security architectures for Digital rights management (DRM) systems use either Public Key Cryptography (PKC) or Identity-based Public Key Cryptography (ID-PKC). However, PKC has a complex certificate management and ID-PKC has a key escrow problem. Certificateless Public Key Cryptography (CL-PKC) has some attractive properties which seem compatible with the requirements of DRM sys...

A Three Party password Authenticated Key Exchange protocol (3PAKE) facilitates two clients to establish authenticated session keys via the help of a trusted server. This approach enhances the scalability of key agreement issue and facilitates users’ convenience in distributed environments. In this paper, we show the security weaknesses of previous works, and then propose our new scheme, using p...

Leakage attacks, including various kinds of side-channel attacks, allow an attacker to learn partial information about the internal secrets such as the secret key and the randomness of a cryptographic system. Designing a strong, meaningful, yet achievable security notion to capture practical leakage attacks is one of the primary goals of leakage-resilient cryptography. In this work, we revisit ...

Suppose that there are players in two hierarchical groups and a computationally unlimited eavesdropper. Using a random deal of cards, a player in the higher group wishes to send a one-bit message information-theoretically securely either to all the players in her group or to all the players in the two groups. This can be done by the so-called 2-level key set protocol. In this paper we give a ne...

In AFRICACRYPT 2010, Abdalla et al. first proposed a slight modification to the computations steps of the BD protocol, called mBD+P. Then they extended mBD+P protocol into mBD+S protocol. In this paper, we show that both of mBD+P and mBD+S protocols are vulnerable to malicious insiders attack. Further, we propose a simple countermeasure against this attack.

Recent advances in the design and analysis of secure two-party key exchange (2KE) such as the leakage of ephemeral secrets used during the attacked sessions remained unnoticed by the current models for group key exchange (GKE). Focusing on a special case of GKE — the tripartite key exchange (3KE) — that allows for efficient one-round protocols, we demonstrate how to incorporate these advances t...