Symmetric Key Encryption

Symmetric encryption is usually considered less safe than asymmetric encryption. This is not because the algorithms are less secure than asymmetric encryption, but because the key that is used to unlock the content must be shared by more than one party. The following diagram illustrates how symmetric encryption works, in general terms.

Figure 10.1: Symmetric encryption

You can create keys for symmetric encryption in this way:

Key key = KeyGenerator.getInstance(<algorithm>).generateKey();

One of the most popular symmetric encryption methods today is the Advanced Encryption Standard (AES).

Exercise 1: Encrypting the String Using Advanced Encryption Standard

In this exercise, we will encrypt the "My secret message" string using AES:

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