Encryption basics and protocols

Encryption is the process of converting information that can be read by everyone – that is, cleartext or plaintext – into secret information called ciphertext that can only be accessed by authorized users.

Encryption requires an algorithm and a key. The algorithm is a mathematical procedure made up of a series of calculations, while the key is a string of bits. The smarter the algorithm is and the longer the key is, the more difficult it will be to break it.

Services provided by encryption

Encryption is a service that hides the content of the data. Encryption does not authenticate the source of the data, it does not hide the source and destination of the data, and it does not check the integrity of the data. For these purposes, we have other mechanisms that we talk about later in this chapter:

Figure 3.1 – Sending information during encryption

An example of the information that is seen and hidden...