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,...

Signature schemes that are derived from three move identi cation schemes such as the Fiat-Shamir, Schnorr and modi ed ElGamal schemes are a typical class of the most practical signature schemes. The random oracle paradigm [1, 2, 12] is useful to prove the security of such a class of signature schemes [4, 12]. This paper presents a new key technique, \ID reduction", to show the concrete security...

Signature schemes that are derived from three move identification schemes such as the Fiat-Shamir, Schnorr and modified ElGamal schemes are a typical class of the most practical signature schemes. The random oracle paradigm [1,2,12] is useful to prove the security of such a class of signature schemes [4,12]. This paper presents a new key technique, “ID reduction”, to show the concrete security ...

In this article the immunity of ElGamal and related signature schemes against fault cryptanalysis (FA) is examined. Although such schemes have been widely adopted, their resistance against fault cryptanalysis has not been verified in detail. Majority of those schemes are not immune to fault cryptanalysis and can be broken without solving discrete logarithm problem. It will be proved that the se...

In this paper, we present another tree-structure signature scheme based on discrete logarithm problem modulo p, where p is a large prime. The basic signing algorithm is the original ELGmal signature scheme. The scheme attains ideal security, i.e, finding existential forgeries under adaptively chosen message attacks is equivalent to solving the discrete logarithm of any random integer y ∈ Z∗ p ....

MANET is an independent and infrastructureless network comprising of self configurable mobile nodes connected via wireless links. MANET is susceptible to various attacks because of some loopholes present in MANET like dynamic topology, zero central administration, limited physical security etc. MANET is prone to numerous malicious attacks one such attack among them is SYBIL ATTACK. In Sybil att...

This research investigates the applications of homomorphic encryption systems in electronic voting schemes. We make use of Paillier cryptosystem which exhibits additive homomorphic properties. The other homomorphic cryptosystems RSA and Elgamal are not considered, since they exhibit only multiplicative homomorphic property. Our proposed method increases the level of security when compared to El...

An efficient and non-interactive deniable authentication protocol is presented to enable a receiver to identify the source of a given message, but not prove the identity of the sender to a third party. The proposed protocol is based on the generalized ElGamal signature scheme and is more efficient than the previous protocols. We show that if an adversary could forge signatures of this protocol,...