Since the inception of the Diffie-Hellman protocol in 1976, it has been an elusive open problem to construct a one-round group key exchange (GKE) protocol. In this paper, we investigate the open problem and answer it in a modular way. We first revisit the GKE definition and distinguish the conventional (symmetric) group key exchange from asymmetric group key exchange (ASGKE) protocols. In the l...

At the beginning some results from the field of graph theory are presented. Next we show how to share a secret that is proper n-coloring of the graph, with the known structure. The graph is described and converted to the form, where colors assigned to vertices form the number with entries from Zn. A secret sharing scheme (SSS) for the graph coloring is proposed. The proposed method is applied t...

We rst present two tight lower bounds on the size of the secret keys of each user in an unconditionally secure one-time use broadcast encryption scheme (OTBES). Then we show how to construct a computa-tionally secure multiple-use broadcast encryption scheme (MBES) from a key predistribution scheme (KPS) by using the ElGamal cryptosystem. We prove that our MBES is secure against chosen (message,...

Cryptosystem designers frequently assume that secrets will be manipulated in closed, reliable computing environments. Unfortunately, actual microchips leak information about the operations they process. Cryptosystems often take slightly different amounts of time to process different inputs and also internal signals. By carefully measuring the amount of time required to perform private key opera...

Identity-Based Encryption is a public key cryptosystem that uses the receiver identifier information such as email address, IP name and etc, to compute private in encrypt message. A message can obtain secret corresponding with his privacy from Private Key Generator he decrypt ciphertext. In this paper, we review Boneh-Franklin’s scheme use bilinear map Weil pairing’s properties propose an ident...

The HFE (Hidden Field Equations) cryptosystem is one of the most interesting public-key multivariate scheme. It has been proposed more than 10 years ago by Patarin and seems to withstand the attacks that break many other multivariate schemes, since only subexponential ones have been proposed. The public key is a system of quadratic equations in many variables. These equations are generated from...

This book provides a very clear, complete and highly illustrated presentation of power analysis methods used to extract secret information from cryptosystems such as smart cards. All concepts are progressively introduced, mathematically analyzed and illustrated using many real attacks results. The main attack methods and some variants are presented. Standard countermeasures used to protect cryp...

AbstrucfIn 1984, Shamir introduced the concept of an identity-based cryptosystem. In this system, each user needs to visit a key authentication center (KAC) and identify himself before joining a communication network. Once a user is accepted, the KAC will provide him with a secret key. In this way, if a user wants to communicate with others, he only needs to know the “identity” of his communica...

Steganography literally means "covered writing", which is derived from the Greek στεγοσ (roof) and γραπηια (writing). Cryptography, watermarking and stenography are closely related [Johnson and Jajodia 1998]. This paper introduces the basis of a wavelet-based low-throughput secret key steganography system that requires the exchange of a secret key (stego-key) prior to communication. We try to t...