This chapter considers eight applications of cryptography. These essentially act as case studies relating to all the previous material. For each application, we identify the security requirements, the application constraints, the choice of cryptography used, and the ways that the keys are managed. We begin with the SSL/TLS protocols used to secure Internet communications. We then examine the cryptography used in W-Fi networks, showing that early cryptographic design mistakes have subsequently been corrected. We then examine the evolving cryptography used to secure mobile telecommunications. This is followed by a discussion of the cryptography that underpins the security of payment card transactions. We look at the cryptography of video broadcasting and identity cards. We then examine the cryptography behind the Tor project, which use cryptography to support anonymous communication on the Internet. Finally, we examine the clever cryptographic design of Bitcoin, showing how use of cryptography can facilitate digital currency.
