Ασφάλεια συστημάτων ηλεκτρονικού ταχυδρομείου
Electronic mail communication protocols aim to provide email services with guaranteed end-to-end message delivery, as well as common formatting for different implementations. Email it is a powerful tool, since it can be used to exchange not only text messages but other more complex types of information, such as sound, image and video. The capabilities for instant and massive message exchange through an inexpensive communication medium, leads to exploitation of its capabilities by malicious users, for example for sending emails with malicious or unwanted content or messages intending to deceive the recipient. Cryptography is a very effective mechanism that can provide adequate security for the majority of threats targeting email. In this thesis the building blocks of email protocols are studied. Then the threats that exploit vulnerabilities of the email mechanism are analyzed and instructions are given on how to safeguard, both the server side and the end-user side. A series of practical experiments are presented, in order to evaluate the efficiency of the examined security controls against the examined threats.