Optimistic fair exchange (OFE) is a protocol for solving the problem of exchanging items or services in a fair manner between two parties, a signer and a verifier, with the help of an arbitrator which is called in only when a dispute happens between the two parties. In almost all the previous work on OFE, after obtaining a partial signature from the signer, the verifier can present it to others...

We introduce the first secure Certificateless Public Key Encryption (CL-PKE) scheme against a malicious Key Generation Center (KGC) in the standard model. Recently, Au et al. [3] pointed out that the previous security models for CL-PKE schemes cannot guarantee the security against a malicious KGC. They also showed that although some schemes are secure against malicious KGC, they require the ran...

A scheme of grouping key distribution based on polynomial protocol is proposed and experimentally demonstrated. The grouping idea is ingeniously used in the design of key distribution. The performance is experimental demonstrated by comparing with kinds of random key pre-distribution schemes. The results show that it can not only guarantee the key connected rate but also strengthen the security...

Key establishment in sensor networks is a challenging problem because asymmetric key cryptosystems are unsuitable for use in resource constrained sensor nodes, and also because the nodes could be physically compromised by an adversary. We present three new mechanisms for key establishment using the framework of pre-distributing a random set of keys to each node. First, in the q-composite keys s...

Abs t rac t . Path keys are secrets established between communicating devices that do not share a pre-distributed key. They are required by most key pre-distribution schemes for sensor networks, because topology is unknown before deployment and storing complete pairwise-unique keys is infeasible for low-cost devices such as sensors. Unfortunately, path keys have often been neglected by existing...

Learning about Recycling and Reuse through Pre-School Games S.M. Shobeyri, Ph.D. H. Meybodi A. Saraadipoor S. Rashidi Environmental education is the most fundamental approach to environmental protection and can begin from the pre-school level and through the use of games. To show the effectiveness of this approach, a random sample of 30 preschoolers of ages 5 and 6 was se...