This ebook is the first authorized digital version of Kernighan and Ritchie's 1988 classic, The C Programming Language (2nd Ed.). One of the best-selling programming books published in the last fifty years, "K&R" has been called everything from the "bible" to "a landmark in computer science" and it has influenced generations of programmers. Available now for all leading ebook platforms, this concise and beautifully written text is a "must-have" reference for every serious programmers digital library.

As modestly described by the authors in the Preface to the First Edition, this "is not an introductory programming manual; it assumes some familiarity with basic programming concepts like variables, assignment statements, loops, and functions. Nonetheless, a novice programmer should be able to read along and pick up the language, although access to a more knowledgeable colleague will help."

The C programming language

Editor's note:Today's integrated circuits are vulnerable to hardware Trojans, which are malicious alterations to the circuit, either during design or fabrication. This article presents a classification of hardware Trojans and a survey of published techniques for Trojan detection.

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A Survey of Hardware Trojan Taxonomy and Detection

The Internet is a major technological advancement reshaping not only our society but also that of universities worldwide. In light of this, universities have to capitalise on the Internet for teaching, and one progressive development of this is the use of online delivery methods. This paper draws upon the results of a survey conducted amongst students enrolled in one online management course at an Australian university. Three critical success factors in online delivery are identified: technology, the instructor and the previous use of the technology from a student’s perspective. We also argue that the lecturer will continue to play a central role in online education, albeit his or her role will become one of a learning catalyst and knowledge navigator.

Critical success factors in online education

Trusted IC design is a recently emerged topic since fabrication factories are moving worldwide in order to reduce cost. In order to get a low-cost but effective hardware trojan detection method to complement traditional testing methods, a new behavior-oriented category method is proposed to divide trojans into two categories: explicit payload trojan and implicit payload trojan. This categorization method makes it possible to construct trojan models and then lower the cost of testing. Path delays of nominal chips are collected to construct a series of fingerprints, each one representing one aspect of the total characteristics of a genuine design. Chips are validated by comparing their delay parameters to the fingerprints. The comparison of path delays makes small trojan circuits significant from a delay point of view. The experimentpsilas results show that the detection rate on explicit payload trojans is 100%, while this method should be developed further if used to detect implicit payload trojans.

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Hardware Trojan detection using path delay fingerprint

Security of a computer system has been traditionally related to the security of the software or the information being processed. The underlying hardware used for information processing has been considered trusted. The emergence of hardware Trojan attacks violates this root of trust. These attacks, in the form of malicious modifications of electronic hardware at different stages of its life cycle, pose major security concerns in the electronics industry. An adversary can mount such an attack with an objective to cause operational failure or to leak secret information from inside a chip-e.g., the key in a cryptographic chip, during field operation. Global economic trend that encourages increased reliance on untrusted entities in the hardware design and fabrication process is rapidly enhancing the vulnerability to such attacks. In this paper, we analyze the threat of hardware Trojan attacks; present attack models, types, and scenarios; discuss different forms of protection approaches, both proactive and reactive; and describe emerging attack modes, defenses, and future research pathways.

Hardware Trojan Attacks: Threat Analysis and Countermeasures

In order to ensure trusted in---field operation of integrated circuits, it is important to develop efficient low---cost techniques to detect malicious tampering (also referred to as Hardware Trojan ) that causes undesired change in functional behavior Conventional post--- manufacturing testing, test generation algorithms and test coverage metrics cannot be readily extended to hardware Trojan detection In this paper, we propose a test pattern generation technique based on multiple excitation of rare logic conditions at internal nodes Such a statistical approach maximizes the probability of inserted Trojans getting triggered and detected by logic testing, while drastically reducing the number of vectors compared to a weighted random pattern based test generation Moreover, the proposed test generation approach can be effective towards increasing the sensitivity of Trojan detection in existing side---channel approaches that monitor the impact of a Trojan circuit on power or current signature Simulation results for a set of ISCAS benchmarks show that the proposed test generation approach can achieve comparable or better Trojan detection coverage with about 85% reduction in test length on average over random patterns

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MERO: A Statistical Approach for Hardware Trojan Detection

There have been serious concerns recently about the security of microchips from hardware trojan horse insertion during manufacturing. This issue has been raised recently due to outsourcing of the chip manufacturing processes to reduce cost. This is an important consideration especially in critical applications such as avionics, communications, military, industrial and so on. A trojan is inserted into a main circuit at manufacturing and is mostly inactive unless it is triggered by a rare value or time event; then it produces a payload error in the circuit, potentially catastrophic. Because of its nature, a trojan may not be easily detected by functional or ATPG testing. The problem of trojan detection has been addressed only recently in very few works. Our work analyzes and formulates the trojan detection problem based on a frequency analysis under rare trigger values and provides procedures to generate input trigger vectors and trojan test vectors to detect trojan effects. We also provide experimental results.

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Towards trojan-free trusted ICs: problem analysis and detection scheme

Hardware Trojan attack in the form of malicious modification of a design has emerged as a major security threat. Sidechannel analysis has been investigated as an alternative to conventional logic testing to detect the presence of hardware Trojans. However, these techniques suffer from decreased sensitivity toward small Trojans, especially because of the large process variations present in modern nanometer technologies. In this paper, we propose a novel noninvasive, multiple-parameter side-channel analysisbased Trojan detection approach. We use the intrinsic relationship between dynamic current and maximum operating frequency of a circuit to isolate the effect of a Trojan circuit from process noise. We propose a vector generation approach and several design/test techniques to improve the detection sensitivity. Simulation results with two large circuits, a 32-bit integer execution unit (IEU) and a 128-bit advanced encryption standard (AES) cipher, show a detection resolution of 1.12 percent amidst ±20 percent parameter variations. The approach is also validated with experimental results. Finally, the use of a combined side-channel analysis and logic testing approach is shown to provide high overall detection coverage for hardware Trojan circuits of varying types and sizes.

Hardware Trojan Detection by Multiple-Parameter Side-Channel Analysis

Malicious alterations of integrated circuits during fabrication in untrusted foundries pose major concern in terms of their reliable and trusted field operation. It is extremely difficult to discover such alterations, also referred to as “hardware Trojans” using conventional structural or functional testing strategies. In this paper, we propose a novel non-invasive, multiple-parameter side-channel analysis based Trojan detection approach that is capable of detecting malicious hardware modifications in the presence of large process variation induced noise. We exploit the intrinsic relationship between dynamic current (I DDT ) and maximum operating frequency (F max ) of a circuit to distinguish the effect of a Trojan from process induced fluctuations in I DDT . We propose a vector generation approach for I DDT measurement that can improve the Trojan detection sensitivity for arbitrary Trojan instances. Simulation results with two large circuits, a 32-bit integer execution unit (IEU) and a 128-bit Advanced Encryption System (AES) cipher, show a detection resolution of 0.04% can be achieved in presence of ±20% parameter (V th ) variations. The approach is also validated with experimental results using 120nm FPGA (Xilinx Virtex-II) chips.

Multiple-parameter side-channel analysis: A non-invasive hardware Trojan detection approach

In this paper we present a new test data compression technique and an associated decompression scheme for testing VLSI chips. Our method is based on our novel use of the much utilized, in software, LZW, particularly LZ77 algorithm. We adapt LZ77 to accommodate bit strings rather than character sets. Moreover, we exploit the large presence of don't cares in the uncompressed test sets that we generated using commercial ATPG tools. Our decompression scheme makes effective use of the on chip boundary scan during decompression and then feeding the internal multiple scan chains for testing. The hardware overhead cost for this scheme is minimal. Experimental results are provided.

Francis Wolff

Papers

MERO: A Statistical Approach for Hardware Trojan Detection

Towards trojan-free trusted ICs: problem analysis and detection scheme

Hardware Trojan Detection by Multiple-Parameter Side-Channel Analysis

Multiple-parameter side-channel analysis: A non-invasive hardware Trojan detection approach

Multiscan-based test compression and hardware decompression using LZ77