Abstract A controller area network (CAN, ISO-11898:2003) is the central nervous system of contemporary, high-tech vehicles, which links electronic control units (ECUs) to offer a distinctive driving experience through data communication. We propose a lightweight cryptographic algorithm SCAN-C with a unique architecture to secure data communication over the CAN bus in contemporary vehicles. It is a 64-bit block cipher supporting a 160-bit primary key with 12 iterative rounds. The proposed algorithm has a unique hybrid architecture with two structural combinations. The key generation schedule has multiplexers, linear feedback shift registers, and a nonlinear function. The encryption schedule has a Feistel and uniform substitution-permutation network. The decryption schedule is the same as the encryption, with keys applied in reverse order. The innovative architecture of SCAN-C exhibits low consumption of resources (1197 gate equivalents to implement in hardware), better security with low iterative rounds, and optimal energy efficiency. The experimental results suggest that the SCAN-C is suitable for implementation in hardware and software.

As more and more programming environments incorporate explicit process descriptions, generic process capabilities will become crucial to the convenient instantiation and maintenance of process description. However, partly because process modeling languages have followed the example of programming languages in general, they are surprisingly weak in supporting generic process descriptions.We propose mechanisms whereby generic process capability can be added to any process formalism. The generic portions of the process description can then be refined through instantiation. We define a system architecture in which a generic process description can be refined gradually during its enactment. Such capabilities will be crucial to incorporating explicit process descriptions into the program environments of the future.

The authors focus on one class of schema revisions necessitated by a very basic phenomenon: a given individual object evolves into a family of objects which are similar to it in many ways. This is commonly called the version problem. In theoretical terms, one can handle the above schema change in the standard, object-oriented database models by the interposition of suitable abstractions into the existing type lattice. There are practical and engineering difficulties with such schema changes. The authors propose an incremental mechanism called instance inheritance which is well suited to handling the schema changes without the attendant practical costs. The authors formally characterize this augmentation to the standard database models, and show examples of its applications.>

Software configuration management ( SCM) is an emerging discipline. An important aspect of realizing SCM is the task of maintaining the configurations of evolving software systems. In this paper, we provide an approach to resolving some of the conceptual and technical problems in maintaining configurations of evolving software systems. The approach provides a formal basis for existing notions of system architecture. The formal properties of this view of configurations provide the underpinnings for a rigorous notion of system integrity, and mechanisms to control the evolution of configurations. This approach is embodied in a language, NuMIL, to describe software system configurations, and a prototype environment to maintain software system configurations. We believe that the approach and the prototype environment offer a firm base to maintain software system configurations and, therefore, to implement SCM.

This correspondence generalizes Hayes' recent ideas for generating an optimal transition write sequence which forms the "backbone" of his algorithm for testing semiconductor RAM's for pattern-sensitive faults. The generalization, presented in graph theoretic terms, involves two sequential steps. The frmst step results in assigning of a "color" to each memory cell. In the second step, each color is defined as a distinct sequence of bits representing the sequence of states assumed by the correspondingly colored cell. The constraints imposed at each step lead to interesting and general problems in graph theory: the standard graph coloring problem in the first step, and a path projection problem from a binary m-cube to a subcube in the second step. Applications to arbitrary k-cell neighborhoods, and particularly to three-cell neighborhoods are shown.