In this paper, we introduce a new cryptographic primitive, called adaptable ciphertext-policy attribute-based encryption (CP-ABE). Adaptable CP-ABE extends the traditional CP-ABE by allowing a semitrusted proxy to modify a ciphertext under one access policy into ciphertexts of the same plaintext under any other access policies; the proxy, however, learns nothing about the underlying plaintext. ...

Service composition is a fundamental technique for developing web-service applications. In general, a single service is not enough to achieve the user’s goal, rather several services, often from different providers, are composed dynamically to satisfy a request. Ensuring security in such a system is challenging and not supported by most of the security frameworks proposed in current literature....

INTRODUCTION With the proliferation of Internet access and the shift to performing some brick-and-mortar transactions online, the need for stability and reliability in the E-commerce arena is becoming increasingly apparent. E*Trade, one of the many successful E-commerce sites, depends completely upon its online presence to stay in business. An outage, regardless of cause, can potentially cost m...

Privacy is recognised as a fundamental requirement for eHealth systems. Proposals to achieve privacy have been put forth in literature, most of which approach patient privacy as either an access control or an authentication problem. In this paper, we investigate privacy in eHealth as a communication problem, since future eHealth systems will be highly distributed and require interoperability of...

A formal model is pr.:sented which represents the .~'tructure underlying temporal references" in natural language. Sei'ting as a framework for analysis o f tenses, time relations, and other references to time i~: language, the model consists o f a partially ordered set, called "'time" and successively def,:ned concepts such as "'tinw.segment", "duration "'~, "'time.segment relation", "'tense", ...

This paper presents a formal model that interprets authorization policy behaviors. The model establishes a connection of applying authorization policies on an administration domain with dissecting the domain into the authorized, denied, and undefined divisions. This connection enables us to analyze authorization policy development problems such as policy merge, inconsistency, ambiguity, and red...

Enterprises such as companies, universities or institutes keep much documents, databases and/or softwares for their own functions. Such data materials should be managed properly. One of the important issues on management of materials is access control. This paper presents a formal model of access control of data materials in an organization that consists of a number of user groups. The model pr...

In recent years, online retailers (e-tailers) have started allowing manufacturers direct access to their customers while charging a fee for providing this access, a format commonly referred to as agency selling. In this paper, we use a stylized theoretical model to answer a key question that e-tailers are facing: When should they use an agency selling format instead of using the more convention...

We present a formal, tool-supported approach to the design and maintenance of access control policies expressed in the eXtensible Access Control Markup Language (XACML). Our aim is to help developers evaluate the consequences of policy decisions in complex situations where security requirements change and access decisions may depend on the external dynamic environment. The approach applies the ...

Polymer latexes are being increasingly used in the construction industry as modifiers, especially in hydraulic cement concrete and mortar. Figure 1 presents polymeric latexes used as cement modifiers. Among the different presentations of polymeric latexes, elastomers are the most widely used (Ohama, 1995). In practice, there are two basic elastomers applicable to cement mixes and these are natu...