A message on the Internet is sent through several networks and via different stations on its way to the target system. The individual stations are responsible for ensuring that the message is properly forwarded and finally delivered to the correct recipient. Each of these stations, if the message is sent in plain text, can receive the message and read its content. This means that a potential attacker, if he controls one of these intermediate systems, can also read the content of the message and even modify it before retransmitting it. Such attacks can have an extreme impact on communication, as information is no longer confidential and the credibility of the message can no longer be established.
For this reason, encryption procedures are used to ensure that the content of messages can only be interpreted by the sender and the recipient. This ensures that the information remains confidential. Furthermore, there are procedures that can be used to detect whether there has been a change in the information in a message. These security procedures are currently in widespread use and are used in particular for sensitive services such as online banking.
In this course we will look at how and whether your connection to online banking is secure or whether the content of an e-mail is trustworthy. For this we will deal with the basics of cryptography, security objectives and different types of encryption. In addition, we will provide insights into different models and standards that are used in practice.