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SUMMARY Ciphertext-policy attribute-based proxy re-encryption (CP-ABPRE) extends the traditional Proxy Re-Encryption (PRE) by allowing a semi-trusted proxy to transform a ciphertext under an access policy to another ciphertext with the same plaintext under a new access policy (i.e., attribute-based re-encryption). The proxy, however, learns nothing about the underlying plaintext. CP-ABPRE has many real world applications, such as fine-grained access control in cloud storage systems and medical records sharing among different hospitals. All the existing CP-ABPRE schemes are leaving chosen-ciphertext attack (CCA) security as an interesting open problem. This paper, for the first time, proposes a new CP-ABPRE scheme to tackle the problem. The new scheme supports attribute-based re-encryption with any monotonic access structures. Despite being constructed in the random oracle model, our scheme can be proven CCA secure under the decisional q-parallel bilinear Diffie-Hellman exponent assumption. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Anonymous receiver encryption is an important cryptographic primitive. It allows a sender to use the public identities of multiple receivers to encrypt messages so that only the authorized receivers or a privileged set of users can decrypt the messages, and the identities of the receivers are not revealed. Recently, Zhang et al. proposed a novel anonymous multi-receiver encryption scheme and claimed that their scheme could realize the receiver's identity privacy. Unfortunately, in this paper, we pointed out that the scheme by Zhang et al. did not achieve the anonymity of the receiver identity after analyzing the security of the scheme. At the same time, we give the corresponding attack. After analyzing the reason to produce such attacks, a novel anonymous multi-receiver encryption scheme is given to achieve the anonymity of the receiver's identities. And we formally prove that the proposed scheme is semantically secure for confidentiality and receiver identities' anonymity. The security of the scheme is based on decisional bilinear Diffie-Hellman problem. Compared with the scheme by Zhang et al., Fan et al., Wang et al., and Chien et al., our scheme is shown to be better performance and robust security. To the best of our knowledge, our scheme is most efficient in terms of computational cost and communication overhead. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In three-party password-based key exchange protocol, a client is allowed to share a human-memorable password with a trusted server such that two clients can negotiate a session key to communicate with each other secretly. Recently, many three-party password-based key exchange protocols have been developed. However, these proposed schemes cannot simultaneously achieve security and efficiency. Based on elliptic curve cryptography (ECC), this paper will propose a new simple three-party password-based authenticated key exchange scheme. The proposed method not only reduces computation cost for remote users and a trusted server but also is more efficient than previously proposed schemes. It is better suited for resource constrained devices, such as smart cards or mobile units. Copyright © 2010 John Wiley & Sons, Ltd. Recently, many three-party password-based key exchange protocols have been developed. However, these proposed schemes cannot simultaneously achieve security and efficiency. Based on elliptic curve cryptography (ECC), this paper, will propose a new simple three-party password-based authenticated key exchange protocol. The proposed method not only reduces computation cost for remote users and a trusted server but also is more efficient than previously proposed schemes. It is better suited for resource constrained devices, such as smart cards or mobile units. Copyright © 2010 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In order to establish encrypted communications in deployable sensor networks, it is essential that encryption keys be shared between nodes. However, the sharing of keys is not simple given the restricted resources of such devices. In recent years, several random key predistribution schemes have been proposed; in the scheme proposed by Du and colleagues, improved performance is achieved by using information regarding the deployment location when predistributing keys. However, this scheme suffers from the problem that it is possible to apply only for the so-called group deployment model whereby nodes are partitioned into groups and deployed from locations that are arranged systematically. In this paper we propose a random key predistribution scheme that can be applied to arbitrary deployment models by making use of probability distribution information regarding the deployment when the key predistribution is performed. In addition, we confirm from computational experiments that this method is able to construct networks that are more consolidated than those created by Du and colleagues' scheme. © 2007 Wiley Periodicals, Inc. Electron Comm Jpn Pt 2, 90(10): 73–83, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjb.20390 [ABSTRACT FROM AUTHOR]