Adoption of Personal Health Record (PHR) applications has been slow due to consumers' concerns in security, privacy and trust, and the challenges in interoperability and integration with other Electronic Medical Record (EMR) systems. This paper proposes the design for a secure interoperable cloud-based PHR service. To enhance the portability and interoperability, we use the Continuity of Care Document (CCD) for both storing and exchanging the PHR information for an individual. To provide self-protecting security for each CCD instance, we apply a broad spectrum of security mechanisms - including access control, encryption, and digital signature - in an integrated, embedded, and fine-grained manner, based on open standards such as eXtensible Access Control Markup Language, XML Encryption, XML Signature, and XML Key Management Specification. To support patient-controlled encryption and privacy-preserving keyword search, we use ciphertext-policy attribute-based encryption and public-key encryption with keyword search schemes, again in an integrated, embedded, and fine-grained manner.

We target at one newly introduced security concern which is not fully addressed when moving (encrypted) data to the cloud, namely, the security of the search results from the cloud. The cloud storage provider (CSP) might be compromised or simply act maliciously for their own good, which yields incorrect search results. In this paper, we exploit hidden vector encryption to tackle this important security problem. Our construction enables CSPs to provide a proof of the search results to be verified later by the cloud storage users. In particular, this proposed scheme handles equality and range searches on encrypted data. Users can verified the correctness of the search results without decrypting for the corresponding file contents. Any tampering with the search results by CSPs will be caught, while any incorrect charge against CSPs for tampering search results can be rectified. Finally, we present extensive security and performance analysis to show the security and practicality of our scheme.

Cloud computing enables a new paradigm of information and communication resources on demand. Users, enterprises, governments start to consider moving their data into the cloud to enjoy its storage capacity and computation capability. Related data confidentiality, integrity and authentication have been extensively investigated, while newly introduced security concern is not fully addressed, namely, the security of the query results. The cloud storage providers (CSPs) might not be fully trusted and susceptible to be compromised. In addition, the CSPs might deliberately search only part of user data for their own purpose, or they might just be incompetent to carry out complex search requests, which yield incorrect query replies. Therefore, an authentication mechanism of query results is required to enable cloud users not only to protect the security of the data in the cloud, but also to verify the correctness of the query results from the CSPs. In this paper, we propose an efficient authentication scheme for CSPs to provide the proof of a query results and for cloud users to be assured by verifying the proof. We also present extensive security and performance analysis and show that our scheme is secure and efficient for the cloud users.

Permutation arrays have found applications in powerline communication. One construction method for permutation arrays is to map good codes to permutations using a distance-preserving mappings (DPM). DPMs are mappings from the set of all q-ary vectors of a fixed length to the set of permutations of some fixed length (the same or longer) such that every two distinct vectors are mapped to permutations with the same or larger Hamming distance than that of the vectors. A DPM is called distance increasing (DIM) if the distances are strictly increased (except when the two vectors are equal). In this correspondence, we propose constructions of DPMs and DIMs from ternary vectors. The constructed DPMs and DIMs improve many lower bounds on the maximal size of permutation arrays.

In the next generation mobile telecommunications, any third party that provides wireless data services (e.g., mobile banking) must have its own solution for end-to-end security. Existing mobile security mechanisms are based on public-key cryptosystem. The main concern in a public-key setting is the authenticity of the public key. This issue can be resolved by identity-based (ID-based) cryptography where the public key of a user can be derived from public information that uniquely identifies the user. This paper proposes an efficient ID-based encryption algorithm. We actually implement the ID-based encryption schemes and compare the performance to show the advantage of our approach. Our study indicates that our solution outperforms a previously proposed algorithm by 20 - 35%.

Mappings of the set of binary vectors of a fixed length to the set of permutations of the same length are useful for the construction of permutation codes. In this article, several explicit constructions of such mappings preserving or increasing the Hamming distance are given. Some applications are given to illustrate the usefulness of the construction. In particular, a new lower bound on the maximal size of permutation arrays (PAs) is given.

This paper proposes a new approach to simplify the two-dimensional random walk models capturing the movement of mobile users in personal communications services (PCS) networks. Analytical models are proposed for the new random walks. For a PCS network with hexagonal configuration, our approach reduces the states of the two-dimensional random walk from (3n/sup 2/+3n-5) to n(n+1)/2, where n is the layers of a cluster. For a mesh configuration, our approach reduces the states from (2n2-2n+1) to (n/sup 2/+2n+4)/4 if n is even and to (n/sup 2/+2n+5)/4 if n is odd. Simulation experiments are conducted to validate the analytical models. The results indicate that the errors between the analytical and simulation models are within 1%. Three applications (i.e., microcell/macrocell configuration, distance-based location update, and GPRS mobility management for data routing) are used to show how our new model can be used to investigate the performance of PCS networks.

In a dual band personal communications services (PCS) network, heavy traffic areas are covered by microcells which overlay macrocells. In such a network, microcells and macrocells utilize different frequency bands. We propose an analytic model to study the performance of a dual band PCS architecture. Our model assumes that a PCS subscriber has a general residence time distribution in a microcell and the macrocell residence time distribution is derived from the microcell residence time distribution. An iterative algorithm is used to compute the overflow traffic from a microcell to its overlaid macrocell. Then, the call incompletion probability is computed by a macrocell model based on the overflow traffic. Our study indicates that the variance of the microcell residence time distribution and the number of microcells covered by a macrocell have significant effects on the call incompletion probability.

In this paper we propose the incrementally extensible folded hypercube (IEFH) graph as a new class of interconnection networks for an arbitrary number of nodes. We show that this system is optimal fault tolerant and almost regular (i.e., the difference between the maximum and the minimum degree of nodes is at most one.). The diameter of this topology is half that of the incomplete hypercube (IH), the supercube, or the IEH graph. We also devise a simple routing algorithm for the IEFH graph. Further we embed cycles and complete binary trees into this graph optimally.

The proposed network is a pyramid-like network of hypercubes, called pyramided hypercube. A pyramided hypercube containing m levels and having n-cube as basic configuration is denoted by PH(m,n). A PH(m,n) with fixed degree n+2, possesses logarithmic diameter, optimal fault tolerance, and capability of simple routing. The PH(m,n) can be extended smoothly with a constant predefined building block based on its recursive structure such that there is no change in the basic node configuration as we increase the network size. Moreover, links once connected are left undisturbed when the network grows in size. The PH(m,n) is also Hamiltonian.