You will encounter cryptography in many forms throughout this book. It is applied to many different technologies and situations and, as such, is something you need to have a firm grasp of.
Some examples of applied cryptography are:
- Public key infrastructure (PKI)
- Digital certificates
- Authentication
- E-commerce
- RSA
- MD-5
- Secure Hash Algorithm (SHA)
- Secure Sockets Layer (SSL)
- Pretty Good Privacy (PGP)
- Secure Shell (SSH)
In many cases, encryption technologies are not only an important part of a technology or system but a required part that cannot be excluded. For example, e-commerce and similar systems responsible for performing financial transactions cannot exclude encryption for legal reasons. Introducing encryption to a system does not ensure bulletproof security as it may still be compromised—but encryption does make hackers work a little harder.