Mambo, et al.  discussed the delegation of signature power to a proxy signer. Lee, et al.  constructed a strong non-designated proxy signature scheme in which the proxy signer had strong non-repudiation. In this paper, we present an enhancement to their scheme such that the identity of the proxy signer is hidden behind an alias. The identity can be… (More)
Data analysis and accurate forecasts of electricity demand are crucial to help both suppliers and consumers understand their detailed electricity footprints and improve their awareness about their impacts to the ecosystem. Several studies of the subject have been conducted in recent years, but they are either comprehension-oriented without practical merits;… (More)
The UMTS/LTE protocol for mobile phone networks has been designed to offer a limited form of anonymity for mobile phone users. In this paper, we quantify precisely what this limited form of anonymity actually provides via a formal security model. The model considers an execution where the home and roaming network providers are considered as one entity. We… (More)
We study the meter data management systems (MDMS) with a focus on missing data handling, and propose two approaches, called Lookback-N and Sandwich-N, based on the historical data. Using a realistic dataset, we demonstrate that Lookback-N is effective for online processing, and Sandwich-N outperforms the conventional offline approach, in terms of estimation… (More)
The Fiat-Shamir (FS) transform is a popular tool to produce particularly efficient digital signature schemes out of identification protocols. It is known that the resulting signature scheme is secure (in the random oracle model) if and only if the identification protocol is secure against passive impersonators. A similar results holds for constructing… (More)
Recently, Chang and Chan proposed a new key exchange scheme based on the hyperspherical equation. However, we find that the Chang-Chan multiparty key exchange scheme is vulnerable to the malicious participant attack and the modification attack. This paper will show the security flaws in the Chang-Chan scheme.