Encryption

Encryption is the process of converting data into a format in which it cannot be read by an unintended recipient.

When dealing with sensitive data, it is always best practice to encrypt it. The nature of the data will determine the sensitivity. For example, credit card information from your customers can be considered as highly sensitive data, whereas the item being bought could be considered as not very sensitive.

You will probably come across the terms encryption at rest and encryption in transit, referring to how data should be encrypted before being stored (for example, in a database) or transmitted (for example, over a network). We will touch on encryption in transit in a later topic (HTTP/TLS).

In this topic, we will focus on the underlying encryption mechanisms.

Since (good) encryption algorithms are complicated by nature, the general advice is to always use existing encryption algorithms and not invent your own. The strength of an encryption algorithm...