Information security is a general term increasingly used to refer to many aspects related to the security of systems. Today, various types of devices and architectures are interconnected via multiple networking protocols, and users are accessing services transparently from different platforms thanks to digital identity and authentication techniques. While faster and easier access to services is granted and more complex use cases are built, at the same time more sophisticated cyberattacks occur affecting individual systems, organizations, or even critical infrastructures. This course aims to teach the skills needed to perform both the analysis and the high-level design of security solutions for systems, devices, or infrastructure protection. Specific terminology and terms in the information security area will be presented, and the most widely encountered cybersecurity attacks will be introduced, with the help of famous security incidents. The security properties of components and information systems will be extensively discussed through practical examples. Since not every single component in a system can be protected, the risk analysis process will be addressed to identify the possible vulnerabilities, threats, and countermeasures that could be adopted for the protection of the assets. After the high-level presentation of the security problems, the main cryptographic algorithms (staying at the basis of the design in any security solution) will be studied. The methods used for the implementation of the security properties, such as authentication, authorization, integrity, and non-repudiation will be explained, as well as the architectures put in place for trust establishment and keys distribution (e.g., public key infrastructures), and commonly used secure data formats, e.g., the X.509 public key certificates. Specific lectures will cover the most widely used security protocols or architectures in wired networks, like Transport Layer Security (TLS) or IPSec, or in wireless environments, like Wi-Fi Protected Access II (WPA2). Security solutions for the application level will be explained as well, including the protection of e-mail (via S/MIME security formats), security of remote access channels, and security of web applications. Technical mechanisms are not sufficient in today’s interconnected systems, but administrative procedures and regulations are meant to indicate compulsory or forbidden behaviors. Thus, national and international regulations in force will be addressed, and some techniques for forensic analysis.