The Internet of Things (IoT) is considered one of the most significant computing trends of the 21st century so far, causing the number of deployed computing devices to increase dramatically. However, the frequency and severity of attacks against computer systems is increasing with attacks such as Stuxnet and Mirai. This thesis is concerned with securing computing devices by creating bonds between hardware and software to ensure deployed devices only execute the software they are intended to and vice versa. This prevents counterfeiting, device tampering and other attacks. This thesis presents three studies into binding hardware and software. These concern creating secure dependencies between the hardware and software of computing devices. Specifically, this thesis considers mutual dependencies created by bidirectional bonds between hardware and software. The first study defines hardware-software bonds, the problem space and proposes the first bidirectional scheme for binding hardware and software together. The scheme is implemented using an FPGA and analysed for security and performance. The second case considers the deployment of binding schemes. This is considered in a smart city environment by first studying and modelling the security architecture of the problem. Two security models are proposed with associated software provisioning protocols. All the proposals are formally analysed using Tamarin Prover and implemented for Raspberry Pi and laptop computer. The third study combines hardware-software binding with another problem in cyber security - Secure Application Execution. The two problems are compared and set of requirements for simultaneously achieving both is defined. A binding scheme is proposed solving the expanded problem and a prototype Secure Execution Processor equipped with the scheme is presented and analysed. Finally, the thesis concludes by summarising the research presented and highlighting potential areas for future work in binding hardware and software together.