Wireless body area networks (WBANs) consist of many small low-power sensors, through which users could monitor the real-time parameters of patients' physiology remotely. This capability could improve medical care and the monitoring of patients. WBAN devices typically have limited computing, storage, power, and communication capabilities. These limitations restrict the applications that WBANs can support. To enhance the capabilities of WBANs, the concept of cloud-assisted WBANs has been introduced recently. By using cloud computing technologies, cloud-assisted WBANs can provide more efficient processing of patients' physiology parameters and support richer services. In cloud-assisted WBANs, the data of patients' physiology are stored in the cloud. The integrity of the data is very important because these data will be used to provide a medical diagnosis and other medical treatments. To address the issue of integrity in cloud-assisted WBANs, we propose an efficient certificateless public auditing (CLPA) scheme. A security analysis of our proposed CLPA scheme shows that it is provably secure against two types of adversaries (i.e., a type-I adversary can replace users' public keys, and a type-II adversary can access the master key) in an environment of certificateless cryptography. A detailed performance analysis demonstrates that the proposed CLPA scheme yields better performance over a previously proposed CLPA scheme.

Certificateless Public Auditing Scheme for Cloud-Assisted Wireless Body Area Networks

Recently, numerous multireceiver identity-based encryption or identity-based broadcast encryption schemes have been introduced with bilinear pairing and probabilistic map-to-point MTP function. As the bilinear pairing and MTP functions are expensive operations, any cryptographic schemes based on these operations experience high computational burden. The certificateless public key cryptography sidesteps the private key escrow problem occurring in identity-based cryptosystem and certificate management troubles of certificate authority-based public key cryptography CA-PKC. We observed that certificateless multireceiver encryption CL-MRE scheme without pairing and MTP hash function has not yet been considered in the literature. In this paper, we proposed a bilinear pairing and MTP hash-function-free CL-MRE scheme with chosen ciphertext attack resilience. The detailed analyses provide evidence that our scheme achieves forward secrecy, backward secrecy, and low computation costs than others. The scheme also provides confidentiality of the message and receiver anonymity in the random oracle model with the hardness of computational Diffie-Hellman problem. Copyright © 2014 John Wiley & Sons, Ltd.

Anonymous and provably secure certificateless multireceiver encryption without bilinear pairing

Three-party key agreement protocol is an important cryptographic mechanism for secure communication, which allows two parties authenticate each other with the help of a trusted server. Very recently, Lai et al.’s proposed a novel three-party key agreement protocol using the enhanced Chebyshev chaotic map and claimed their protocol could withstand various attacks. Unfortunately, in this paper, we will show their protocol is vulnerable to the privileged insider attack and the off-line password guessing attack. To solve the problems, we propose an improved three-party key agreement protocol using the enhanced Chebyshev chaotic map. Security analysis and performance analysis show our protocol not only could withstand various attacks, but also has similar performance. Therefore, it is very suitable for practical applications.

Cryptanalysis and improvement of a three-party key agreement protocol using enhanced Chebyshev polynomials

SUMMARY

Recently, He et al. proposed an efficient certificateless signature (CLS) scheme without pairings and demonstrated their scheme to be provably secure in the random oracle model. Unfortunately, Tian and Huang and Tsai et al. pointed out that the scheme cannot withstand a Type II adversary's attack. Tsai et al. also proposed an improved scheme to enhance security. However, the schemes of He et al. and Tsai et al. are not real CLS schemes because the user's public key is used to generate its partial private key. Besides, He et al. and Tsai et al. just demonstrated that their schemes are secure against the normal adversary in the random oracle model. In this paper, we propose a real CLS scheme and demonstrate that our scheme is secure against the super adversary. Security analysis and performance analysis show that our scheme could enhance security and increase computational cost slightly. Copyright © 2012 John Wiley & Sons, Ltd.

Further improvement of a certificateless signature scheme without pairing

Design and analysis of a three party password-based authenticated key exchange protocol using extended chaotic maps

Since certificateless public key cryptography (CLPKC) has received widespread attention due to its efficiency in avoiding key escrow problems in identity-based public key cryptography (ID-PKC), the certificateless authenticated key agreement (CLAKA) protocol, an important part of CLPKC, has been studied a great deal. Most CLAKA protocols are built from pairings which need costly operations. To improve the performance, several pairing-free CLAKA protocols have been proposed. In this paper, we propose a new pairing-free CLAKA protocol. Compared with the related protocols, our protocol has better performance. Also, our protocol is provably secure in a very strong security model-the extended Canetti-Krawczyk (eCK) model.

An efficient certificateless two-party authenticated key agreement protocol

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Jianhua Chen

Papers

An efficient certificateless two-party authenticated key agreement protocol

An efficient certificateless authenticated key agreement scheme