Systematic control and management of data integrity
Integrity has long been considered a fundamental requirement for secure computerized systems, and especially today's demand for data integrity is stronger than ever as many organizations are in-creasing their reliance on data and information systems. A number of recently enacted data privacy regulations also require high in-tegrity for personal data. In this paper, we discuss various issues concerning systematic control and management of data integrity with a primary focus on access control. We first examine some previously proposed integrity models and define a set of integrity requirements. We then present an architecture for comprehensive integrity control systems, which has its basis on data validation and metadata management. We also provide an integrity control policy language that we believe is flexible and intuitive.

title: Privacy preserving schema and data matching
abstract: In many business scenarios, record matching is performed across different data sources with the aim of identifying common information shared among these sources. However such need is often in contrast with privacy requirements concerning the data stored by the sources. In this paper, we propose a protocol for record matching that preserves privacy both at the data level and at the schema level. Specifically, if two sources need to identify their common data, by running the protocol they can compute the matching of their datasets without sharing their data in clear and only sharing the result of the matching. The protocol uses a third party, and maps records into a vector space in order to preserve their privacy. Experimental results show the efficiency of the matching protocol in terms of precision and recall as well as the good computational performance.

title: GEO-RBAC: a spatially aware RBAC
abstract: Securing access to data in location-based services and mobile applications requires the definition of spatially aware access control systems. Even if some approaches have already been proposed either in the context of geographic database systems or context-aware applications, a comprehensive framework, general and flexible enough to cope with spatial aspects in real mobile applications, is still missing. In this paper, we make one step towards this direction and we present GEO-RBAC, an extension of the RBAC model to deal with spatial and location-based information. In GEO-RBAC, spatial entities are used to model objects, user positions, and geographically bounded roles. Roles are activated based on the position of the user. Besides a physical position, obtained from a given mobile terminal or a cellular phone, users are also assigned a logical and device independent position, representing the feature (the road, the town, the region) in which they are located. To make the model more flexible and re-usable, we also introduce the concept of role schema, specifying the name of the role as well as the type of the role spatial boundary and the granularity of the logical position. We then extend GEO-RBAC to cope with hierarchies, modeling permission, user, and activation inheritance.

title: Database Monitoring in U-Datalog

title: T_Chimera: A Temporal Object-Oriented Data Model
abstract: Temporal data models are an active research area. However, although many temporal extensions have been proposed for the relational data model, there is no comparable amount of work in the context of object-oriented data models. This paper presents T―Chimera, a temporal extension of the Chimera object-oriented data model. The main contribution of this work is to define a formal temporal object-oriented data model and to address on a formal basis several issues deriving from the introduction of time in a semantically rich model like the object-oriented one.

title: A model of authorization for next-generation database systems
abstract: The conventional models of authorization have been designed for database systems supporting the hierarchical, network, and relational models of data. However, these models are not adequate for next-generation database systems that support richer data models that include object-oriented concepts and semantic data modeling concepts. Rabitti, Woelk, and Kim  presented a preliminary model of authorization for use as the basis of an authorization mechanism in such database systems. In this paper we present a fuller model of authorization that fills a few major gaps that the conventional models of authorization cannot fill for next-generation database systems. We also further formalize the notion of implicit authorization and refine the application of the notion of implicit authorization to object-oriented and semantic modeling concepts. We also describe a user interface for using the model of authorization and consider key issues in implementing the authorization model.

title: Database Security: Research and Practice
abstract: As an increasing number of organizations become dependent on access to their data over the Internet, the need for adequate security measures is becoming more and more critical. The most popular security measure these days is a firewall. However, a firewall is not immune to penetration, and it does not provide any protection of internal resources from insiders and successful intruders. One of the requirements for the protection of internal resources is access control to ensure that all accesses are authorized according to some specified policy. In this paper, we survey the state of the art in access control for database systems, discuss the main research issues, and outline possible directions for future research.

title: Achieving Stricter Correctness Requirements in Multilevel Secure Database Management Systems
abstract: Although high assurance multilevel secure database management systems (DBMSs) are slowly becoming commercially available, these systems have yet to offer a concurrency control protocol that is free of signaling channels and produces serializable (one-copy serializable when multiple versions of data are maintained) histories. In this paper, we consider the multiversion con currency control algorithm that has been implemented in the Trusted Oracle DBMS. It guarantees levelwise serializability, which is a weaker notion of correctness than one-copy serializability.While level wise serializability has many desirable properties, it suffers from the inconsistent retrieval problems that may seriously harm database integrity. In this paper, we demonstrate how pair wise serializability and one-copy serializability, stricter correctness criteria than levelwise serializability, can be achieved, using the Trusted Oracle scheduler. It is important to note that rather than taking the usual approach of modifying the underlying con currency control protocol such that it meets the stricter correctness requirements, we achieve our goal without modifying the Trusted Oracle con currency control algorithm in any way. In other words, in this paper, we do not propose a new scheduler for con currency control, but propose algorithms, if used with the Trusted Oracle scheduler, to generate pair wise or one-copy serializable histories.Our approach is based on the assumption that all transactions that are running during a certain interval are known in advance. We perform a static analysis of the read-and write-sets of these transactions to recognize conflicts among transactions. The results of the analysis are used to control the order of submission of the transactions in such a way that stricter correctness requirements are met. All the algorithms proposed in this paper are implementable with untrusted code.Submitted to the Journal of Computer Security. 1993; Revised March, 1994