The band theory of solids is developed and used to explain the properties of conductors, insulators, and semiconductors (both pure and doped). Type n and p semiconductors are introduced and combined to form the p-n junction or diode. Analysis of diode circuits is introduced, followed by several applications of diodes. As a lead-in to power supply circuits, rectification, filtering, and regulation are discussed. Zener diodes are introduced and applications are given. The silicon-controlled rectifier and some applications are presented. Photodiode operation and the resulting circuit analysis are given, along with a discussion of optimization. An introduction to switching power supplies (boost, buck, and buck-boost) is presented.

Traditionally, linear cryptanalysis exploits linear approximations with atypically high absolute correlation. In this chapter, we discuss instead how linear approximations with correlation zero can be used. This variant of linear cryptanalysis is called zero-correlation linear cryptanalysis.

A variety of digital devices and circuits are introduced. The use of binary numbers in digital electronics is discussed. The AND, OR, XOR, NOT, NAND, NOR, XNOR, and buffer logic gates are presented, followed by a discussion of implementing logical functions. The Karnaugh map and Boolean algebra are introduced. Different ways of constructing logic gates are presented. Half- and full-adder circuits are developed. Several types of flip-flops are discussed. Building on this foundation, we introduce counters, decoders, shift registers, D/A and A/D converters, multiplexers, demultiplexers, memory arrays, automated processing, programmable logic devices, and digital EM communications.

Oscillator circuits, categorized into relaxation and sinusoidal types, are introduced. Three examples of relaxation oscillators are given and analyzed: the SCR sawtooth, the transistor astable, and the 555 astable. Monostable operation of the 555 timer is also discussed. For sinusoidal oscillators, examples include a transistor RC, an op-amp Wien bridge, a Hartley, and a Pierce oscillator. Oscillator stability is discussed. Electromagnetic communications (AM and FM) are discussed as applications of oscillators.

This chapter presents some of the biomaterials used in different clinical applications. Examples of current commercially available devices are presented, together with the advantages of the biomaterials used for each application and the rationale behind the choice.

Capacitors and inductors are introduced, along with their equivalent circuit laws. Switched RC circuits are thoroughly analyzed. The response of an RC circuit to a sinusoidal drive voltage is analyzed and leads to a discussion of high- and low-pass filters, phase shifters, integrators, and differentiators. The use of complex numbers in circuit analysis is introduced and applied to sinusoidally driven series RC, LR, and LRC circuits as well as the switched LRC circuit. Fourier analysis and its meaning are presented. The operation of transformers is introduced.

If more than one good linear approximation is available, then it is natural to try to exploit all of them simultaneously. This is called multiple linear cryptanalysis. The first part of this chapter discusses multiple linear cryptanalysis in general. The second part focuses on the special case with a set of masks that forms a vector space, which is called multidimensional linear cryptanalysis.

Finding linear trails with high absolute correlation quickly becomes tedious work, especially for ciphers with a more complicated structure than the example that we have worked with so far. Since the total number of trails is finite, finding linear trails with a maximal absolute correlation is an example of a combinatorial optimization problem. This chapter discusses three commonly used optimization methods: Matsui’s branch and bound method, mixed-integer linear programming, and satisfiability or satisfiability modulo theories. At the same time, the chapter introduces two additional example ciphers that follow a different design strategy.