Search

To ensure privacy and security of healthcare wireless medical sensor networks (HWMSNs), several concrete constructions of efficient certificateless aggregate signature (CLAS) scheme without bilinear pairing were proposed in the last few years. However, many previous constructions of CLAS scheme were found to be impractical, which either fail to meet the claimed security or contain design flaws. For example, in some of the previous proposals, any adversary can forge a valid signature on any new message. In this paper, we first demonstrate some security issues and design flaws in the previous proposals of CLAS scheme. As follows, to further address the above deficiencies, a new construction of CLAS scheme with improved security is presented, and the formal security proof is given using Forking Lemma in the random oracle model, assuming that the discrete logarithm problem is hard. Compared with the previous CLAS schemes, our construction has similar computational costs, and it provides better security guarantees. Therefore, compared with the existing solutions, our proposal with strong security and high computational efficiency is more suitable for use in HWMSNs. [ABSTRACT FROM AUTHOR]

Leakage of private information, such as the secret keys, has become a threat to the security of computing systems. It has become a common requirement that cryptographic schemes should withstand various leakage attacks, including the continuous leakage attacks. Although some research progresses have been made toward this area, there are still some unsolved issues. In the literature, the public-key encryption (PKE) constructions with (continuous) leakage resilience normally require the upper bound of leakage to be fixed. However, in many real-world applications, this requirement cannot provide sufficient protection against leakage attacks. In order to mitigate these problems, this paper demonstrates how to design a leakage amplified PKE scheme with continuous leakage resilience and chosen-plaintext attacks security. In our proposed PKE scheme, the leakage parameter can have an arbitrary length. Moreover, the length of permitted leakage in our scheme can be flexibly adjusted according to the leakage requirements of application environment. Its security is formally proved under the classic static assumption. [ABSTRACT FROM AUTHOR]