Chapter 3 introduces the reader to the most relevant technological aspects of blockchain and smart contracts. Specifically, Chapter 3 presents the technological foundations blockchain and smart contracts are built upon, by providing some basic examples, which could help to grasp how this technology works. In addition, it includes an overview of existing, soon to be developed, or potential applications of blockchain and smart contracts in different fields, in order to help the reader understand how they could affect existing processes or, more in general, society.

It is quite likely that smart contracts, which represent a further step in formalizing contracts, will diminish the courts’ ability to intervene through interpretation. In a smart contract context, it is not obvious that the smart contract can go beyond the borders of the program to find relevant rules (off-chain elements and occurrences), limiting therefore the capacity to use blockchain technology in highly contextualized types of contracting. Courts generally come into play when complexity, doubts, and litigation around them arise. In order to assure the smooth development of automated contracts, the courts must develop the expertise to interpret them and smart contracts need to provide for parties to control real world consequences and be able to terminate the contracts if necessary during and after performance.

The author examines the impact of blockchain and smart contracts on the legal profession. After all, the lawyer is entitled to draft smart contracts. For a few years now, in information technology, the lawyer has promoted the writing of so-called ‘agile’ contracts in connection with projects run by ‘agile’ methods. However, the smart contract, whether described as a contract or simple algorithm, challenges the lawyer by its philosophy (‘code is law’) and by its writers who are no longer jurists but developers. He discusses whether this technology will be ‘killing off’ the legal profession. Before over-hastily assuming this apocalyptic demise of the lawyer, the author suggests to think about the role and the status of the lawyer in his general mission of advice and defense, and considers whether information technology can be a substitute for the lawyer or simply a new tool that could be used.

Chapter 3 examines the challenges of applying the cost–benefit analysis theory given the current legal stanrads used by courts. The cost–benefit analysis theory requires quantified costs and benefits, while the current legal system uses broad, descriptive standards to evaluate searches. The chapter notes that the current legal standards are inconsistently applied, and thus provide inadequate guidance to police who are attempting to follow these standards. The chapter also points out a dissonance between how judges apply the current standards and how lay people believe the standards should be applied. The solution is to quantify the legal standards, thus making the standards more transparent, allowing for a greater range of standards, and allowing the judges to use data from predictive algorithms as formal factors in deciding whether to allow a certain type of surveillance. This will also allow courts and policymakers to use the cost–benefit analysis theory more accurately and efficiently.

Chapter 8 discusses the final category of technology enhanced surveillance: hyper-intrusive searches. These searches occur when law enforcement agents use surveillance technology to see and hear private, intimate information that would otherwise be undetectable. This category includes video monitoring of private places and real-time interception of oral or digital communication. This type of surveillance unquestionably needs greater regulation; the question is what form that regulation will take. This chapter notes that courts have a variety of different tools at their disposal that can make hyper-intrusive searches more productive, and provides guidance to courts as to which tools to use for each type of hyper-intrusive search.

Chapter 4 discusses the topic of reactive surveillance, such as thermal imagers, decryption tools, and devices that reveal the phone numbers that are being dialed on a telephone. These are tools which the government needs in order to respond to privacy-enhancing technology used by private citizens. Although reactive surveillance tools can be very intrusive in some ways, in most contexts they are only being used to learn information that would ordinarily be public, but has been hidden by new forms of privacy-enhancing technology, such as heat lamps, encryption tools, and cell phones. In evaluating reactive surveillance, we need to consider both the level of criminal activity that is potentially masked by the privacy-enhancing technology, and how the privacy-enhancing technology has affected society’s expectations of privacy. In the context of encryption, we need to assist law enforcement even further, by creating a key escrow system which will give law enforcement the ability to decrypt any piece of data once they have obtained the proper legal authority

Chapter 2 focuses on the benefits side of the cost–benefit analysis equation, and notes that the rise of big data’s predictive algorithms allow law enforcement to measure the likely success rate of their surveillance with far greater precision than in the past. These predictive algorithms have the potential to revolutionize criminal investigations in many ways, by making them cheaper, more accurate, and less biased. However, the surveillance technologies must be designed in ways to ensure that they meet the Fourth Amendment’s requirement of particularized suspicion and to ensure that they do not rely on tainted data.

Chapter 7 explores a specific aspect of mosaic searches: information that individuals turn over to private companies. Under the controversial third party doctrine, individuals surrender all Fourth Amendment rights when they share information with a third party. Most legal scholars criticize the third-party doctrine as anachronistic and a significant threat to privacy. This chapter will argue that the conventional wisdom is wrong, for two reasons. First, modern information sharing enhances our privacy; thus, some aspects of the third-party doctrine can be classified as reactive surveillance. But more importantly, the cost–benefit analysis theory reveals that this massive private collection of data is a positive-sum shift in surveillance. On the privacy side, corporations themselves can assert their own Fourth Amendment rights to keep this information secret – a phenomenon we are already seeing in many technology companies that store and transfer our data. On the security side, millions of companies are constantly collecting billions of pieces of data, all of which can be available to help solve crimes when the government can meet the appropriate standard to overcome the companies’ Fourth Amendment rights.

Chapter 6 examines mosaic searches, and discusses the potential and challenges created by big data surveillance. Recent developments in surveillance technology allow police to engage in various methods of widespread, low-cost surveillance, from tracking a person’s location through her cell phone to predicting behavior based on a person’s telephone records, credit card purchases, and other publicly available details. These data points will only become more numerous in the near future, as camera-mounted drones and self-driving cars become common. Courts and legislatures have been wary of these developments, and in fact have sought to restrict them because their financial cost is so low that they allow law enforcement to engage in nearly indiscriminate surveillance. But the cost–benefit analysis theory shows that courts should adopt the opposite approach: all other factors being equal, a surveillance method that is less expensive should be encouraged, not restricted. Furthermore, encouraging low cost widespread surveillance will help to even out the massive inequities we now see in government surveillance, where the poor and people of color bear a much greater cost than more enfranchised citizens. Finally, applying the cost–benefit analysis theory will require the government to demonstrate the benefits of indiscriminate surveillance, which will encourage the government to develop and utilize more productive (and less intrusive) methods of surveillance.

Chapter 1 of the book describes the the cost–benefit analysis theory in more detail by examining how to measure the costs of different types of surveillance, particularly their cost to our privacy. Currently the Supreme Court has the task of determining these costs, but it is poorly situated to make these determinations. Under the current regime, the Court usually can only tell us whether the intrusiveness of a certain type of surveillance passes a certain threshold of intrusiveness – that is, whether the surveillance is a “search.” But the cost–benefit theory requires a more precise calculation of the level of intrusiveness; it requires a measurement of the degree to which the surveillance infringes on our privacy. Furthermore, the Supreme Court decides only one or two cases a year on this issue, which is insufficient to keep up with the myriad of new types of surveillance that occur in modern investigations.

The Introduction sets out the problem of applying the Fourth Amendment to modern-day surveillance techniques and compares two different theories that can be used to guide courts and policymakers when they address these questions: the equilibrium adjustment theory to the cost–benefit analysis theory. The chapter concludes that the cost–benefit analysis theory is superior because it is able to evolve as societal expectations of privacy evolve, and because it encourages surveillance methods that create a positive sum change in the trade-off between privacy and security.

The conclusion proposes that legislatures and ultimately administrative agencies need to take the lead to measure the costs and benefits of different types of surveillance. It also proposes four principles to guide courts and policymakers going forward: encourage bunary searches, encourage lower cost surveillance methods, maintain the third party doctrine but enhance the Fourth Amendment rights of corporate third parties; and use existing legal tools to restrict hyper-intrusive searches.

Chapter 5 describes a uniquely productive type of surveillance known as a binary search. Binary searches reveal no information other than the absence or presence of illegal activity. The Supreme Court has correctly determined that a binary search does not implicate the Fourth Amendment, since an individual does not have a legitimate expectation of privacy in illegal conduct. The cost–benefit analysis theory encourages binary searches, because they are the perfect example of positive sum surveillance: if designed properly, they can increase the level of crime detection without increasing the level of privacy infringement. Soon facial recognition technology and advances in crime recognition software will allow law enforcement to achieve nearly 100 percent enforcement for certain crimes. Such a development, though theoretically desirable, has potentially negative side effects.