Authentication is the validation provided by the communicating entity’s identity as the one that it claims to be. Integration of confidentiality, integrity and authentication into web applications is necessary to prevent unscrupulous attacks. For many years, we have been experimenting with methods for introducing important concepts related to secure transactions and improving undergraduate curricula and research experiences for Computer Science and Information Systems students. To achieve this goal, sequence diagrams which represent the progression of events over time are introduced to our students. This paper describes a learning module developed to help students understand authentication and integration of confidentiality, integrity and authentication into modeling web applications using sequence diagrams.