Security and Dependability of Embedded Systems: A Computer Architects' Perspective

Abstract

Designers of embedded systems have traditionally optimized circuits for speed, size, power and time to market. Recently however, the dependability of the system is emerging as a great concern to the modern designer with the decrease in feature size and the increase in the demand for functionality. Yet another crucial concern is the security of systems used for storage of personal details and for financial transactions. A significant number of techniques that are used to overcome security and dependability are the same or have similar origins. Thus this tutorial will examine the overlapping concerns of security and dependability and the design methods used to overcome the problems and threats. This tutorial is divided into four parts: the first will examine dependability issues due to technology effects; the second will look at reliability aware designs; the third, will describe the security threats; and, the fourth part will illustrate the countermeasures to security and reliability issues Part I: Dependability Issues due to Technology Effects and Architectural Countermeasures Moore’s law has been in place for more than four decades. Each new technology node provided advantages in basically all major design constraints (performance, power, area, etc.). When migrating to upcoming technology nodes it will become obvious that this win-win situation soon will be at an end. Or, in other words, in future it becomes far more difficult and expensive to migrate to new technology nodes. One major point is an inherent undependability which will become a challenging problem. Undependability addressed within this part of the tutorial is related to a) Fabrication and Design-Time Effects like “Yield and Process Variations” and “Complexity” as well as b) run-time effects as “Aging Effects”, “Thermal Effects” and “Soft Errors”. The first part of this tutorial will give the details of these effects and a prospect of how these effects might influence future architectures for embedded systems. An overview of selected state-of-the-art paradigms and approaches is given including a focus on organic computing principles as well as run-time adaptive embedded processor architectures that can deal with dependability issues. Part II: Reliability Aware Design for Embedded Systems Design of robust embedded systems meeting stringent quality, reliability, and availability requirements is becoming increasingly difficult in advanced technologies. The current design paradigm which assumes that no gate or interconnect will ever operate incorrectly within the lifetime of a product must change to cope with such failures. New architectural features are required for robust system design with built-in mechanisms for failure tolerance, detection and recovery during normal system operation. This part of the tutorial will focus on new design techniques required for building robust systems: concurrent error detection, recovery, and selfrepair. A broad spectrum of circuit-level, logic-level, micro-architectural, hardware subsystem, and software techniques will be covered; the associated trade-offs among techniques will be presented. Implemented protection mechanisms are determined by a complex evaluation of power