Watermarking is a frequently used tool for digital rights management. An example of this is using watermarks to place ownership information into an object. There are many instances where placing multiple watermarks into the same object is desired. One mechanism that has been proposed for doing this is segmenting the data into a grid and placing watermarks into different regions of the grid. This is particularly suited for images and geographic information systems (GIS) databases as they already consist of a fine granularity grid (of pixels, geographic regions, etc.); a grid cell for watermarking is an aggregation of the original fine granularity cells. An attacker may be interested in only a subset of the watermarked data, and it is crucial that the watermarks survive in the subset selected by the attacker. In the kind of data mentioned above (images, GIS, etc.) such an attack typically consists of cropping, e.g. selecting a geographic region between two latitudes and longitudes (in the GIS case) or a rectangular region of pixels (in an image). The contribution of this paper is a set of schemes and their analysis for multiple watermark placement that maximizes resilience to the above mentioned cropping attack. This involves the definition of various performance metrics and their use in evaluating and comparing various placement schemes.

A common technique for improving performance in a database is to decluster the database among multiple disks so that data retrieval can be parallelized. In this paper we focus on answering range queries in a multidimensional database (such as a GIS), where each of its dimensions is divided uniformly to obtain tiles which are placed on different disks; there has been a significant amount of research for this problem (a subset of which is [1,2,3,4,5,6,7,8,9,11,12,13,14,15]). A declustering scheme would be optimal if any range query could be answered by doing no more than # of tiles inside the range/# of disks retrievals from any one disk. However, it was shown in [1] that this is not achievable in many cases even for two dimensions, and therefore much of the research in this area has focused on developing schemes that performed close to optimal. Recently, the idea of using replication (i.e. placing records on more than one disk) to increase performance has been introduced [7,12,13,15]. If replication is used, a retrieval schedule (i.e. which disk to retrieve each tile from) must be computed whenever a query is being processed. In this paper we introduce a class of replicated schemes where the retrieval schedule can be computed in time O(# of tiles inside the query’s range), which is asymptotically equivalent to query retrieval for the non-replicated case. Furthermore, this class of schemes has a strong performance advantage over non-replicated schemes, and several schemes are introduced that are either optimal or are optimal plus a constant additive factor. Also presented in this paper is a strictly optimal scheme for any number of colors that requires the lowest known level of replication of any such scheme.

Most work on watermarking has resulted in techniques for different types of data: image, audio, video, text/language, software, etc. In this paper we discuss the watermarking of abstract structured aggregates of multiple types of content, such as multi-type/media documents. These semi-structures can be usually represented as graphs and are characterized by value lying both in the structure and in the individual nodes. Example instances include XML documents, complex web content, workflow and planning descriptions, etc. We propose a scheme for watermarking abstract semi-structures and discuss its resilience with respect to attacks. While content specific watermarking deals with the issue of protecting the value in the structure’s nodes, protecting the value pertaining to the structure itself is a new, distinct challenge. Nodes in semi-structures are value-carrying, thus a watermarking algorithm could make use of their encoding capacity by using traditional watermarking. For example if a node contains an image then image watermarking algorithms can be deployed for that node to encode parts of the global watermark. But,  given the intrinsic value attached to it, the graph that “glues” these nodes together is in itself a central element of the watermarking process we propose.  We show how our approach makes use of these two value facets, structural and node-content.

Two main results in the area of information hiding in natural lan-  guage text are presented. A semantically-based scheme dramatically im-  proves the information-hiding capacity of any text through two tech-  niques: (i) modifying the granularity of meaning of individual sentences,  whereas our own previous scheme kept the granularity fixed, and (ii) halv-  ing the number of sentences affected by the watermark. No longer a “long text, short watermark” approach, it now makes it possible to watermark short texts like wire agency reports. Using both the above-mentioned se-  mantic marking scheme and our previous syntactically-based method hides information in a way that reveals any non-trivial tampering with the text (while re-formatting is not considered to be tampering—the problem would be solved trivially otherwise by hiding a hash of the text) with a probabil-  ity 1–2–b(n+1), n being its number of sentences and b a small positive integer based on the extent of co-referencing.

In an open environment such as the Internet, the decision to collaborate with a stranger (e.g., by granting access to a resource) is often based on the characteristics (rather than the identity) of the requester, via digital credentials: Access is granted if Alice’s credentials satisfy Bob’s access policy. The literature contains many scenarios in which it is desirable to carry out such trust negotiations in a privacy-preserving manner, i.e., so as minimize the disclosure of credentials and/or of access policies. Elegant solutions were proposed for achieving various degrees of privacy-preservation through minimal disclosure. In this paper, we present protocols that protect both sensitive credentials and sensitive policies. That is, Alice gets the resource only if she satisfies the policy, Bob does not learn anything about Alice’s credentials (not even whether Alice got access), and Alice learns neither Bob’s policy structure nor which credentials caused her to gain access. Our protocols are efficient in terms of communication and in rounds of interaction.

As organizations increasingly rely on information systems as the primary way to conduct operations, keeping such systems secure requires increasing emphasis. This paper provides information security professionals and top management a framework through which usable security strategy and policy for applications can be created and maintained in line with the standard information technology life cycle. This framework, the Policy Framework for Interpreting Risk in E-Business Security (PFIRES), was initially developed for e-commerce activities and has since been generalized to handle security policy for all types of organizations engaged in computing and Internet operations. This framework offers a possible starting point for understanding a security policy’s impact on an organization, and is intended to guide organizations in developing, implementing, and maintaining security policy.