This paper examines the common threats to data security in open systems highlighting some of the more recent threats, and looks at some of the tools and techniques currently available to enhance the security of a Unix system. Since many programs are written without security issues in mind, the topic of secure programming methodologies is also dicussed, with some examples of coding techniques that avoid security vulnerabilities.

The purpose of this paper is to build the foundation for software architect- ure. We first develop an intuition for software architecture by appealing to several well-established architectural disciplines. On the basis of this intuition, we present a model of software architecture that consists of three components: elements, form, and rationale. Elements are either data , processing or connecting elements. Form is defined in terms of the properties of, and the relationships among, the elements-that is, the constraints of the elements. The rationale provides the underlying basis for the architecture in terms of the system constraints, which most often derive from the system requirements. We discuss the components of the model in the context of both architectures and architectural styles and present an extende example to illustrate some important architectural and style considerations. We conclude by presenting some of the benefits to our approach to software architecture, summarizing our contributions, and relating our approach to other current work

In carrying out its charter to help federal agencies meet their individual information technology (IT) security requirements, the National Institution of Standards and Technology (NIST) must understand what agencies need to meet those requirements.  The intial effort to improve NIST\‘s ability to identify and assess these agency needs consisted of reviewing existing documented sources of IT security-related requirements and needs, conducting and in-depth study, and establishing ongoing mechanisms to facilitate communication between NIST and agencies.  The recently conducted study involved interviews with federal agency staff and a survey in which respondents indicated the importance and immediacy of a set of three dozen candidate needs.  Study participants were selected to represent a wide variety of fereal IT security environments, applications, individual perspectives, and data processing environments. The results of the study contribute to a sound basis for planning future NIST IT security standards, guidance, and related activities. NIST is commited to security standards, guidance, and related activities. NIST is committed to developing and documenting a clear understanding of agency needs in this area and to using the documented, validated, needs as input to its program planning process. This report documents the study.

Experience with the design and implementation of a number of computer systems , and study of many other systems has led to some general hints to system design which are described herr. They are illustrated by a number of examples, ranging from hardware such as the Alto and the Dorado to application programs such as Bravo and Star.