Denial of Service (DoS) attacks are serious threats for network societies. For dealing with DoS attacks, Jakobsson and Juels first proposed the notion of useful client puzzles (UC...
We describe several cryptographic schemes in quadratic function fields of odd characteristic. In both the real and the imaginary representation of such a field, we present a Diffi...
With the explosion of the mobile communication market, more and more handheld devices act as clients in the Internet. People use these devices to purchase books, play games, recei...
Based on the notion of accumulators, we propose a new cryptographic scheme called universal accumulators. This scheme enables one to commit to a set of values using a short accumul...
An additively-homomorphic encryption scheme enables us to compute linear functions of an encrypted input by manipulating only the ciphertexts. We define the relaxed notion of a se...