3.1. Authenticity

Encryption only ensures confidentiality, meaning it prevents unauthorised people from reading the message.

Encryption does not ensure the authenticity of the message. In other words it does not guarantee that the message was created by a specific sender or that it was not altered.

To verify the authenticity of a message we use two techniques:

• Digital signing

• Digital certificates

The first is used to ensure that a message was not tampered by the sender. The second verifies that the sender is who they claim to be.