The reliance of the information society on pervasive networks, mobile computing, online services, and cloud platforms continues to grow. The privacy of human activities and the security of personal data are challenged by today’s information technology in ways never seen before in history. This course focuses on privacy and security in a digital world. It presents cryptographic and non-cryptographic methods relevant for protecting privacy, anonymity, and data security. Topics include pseudonymity, data anonymization and de-anonymization, notions of privacy and privacy regulation, measures for the privacy of data, steganography and traffic hiding, network anonymity, and censorship resistance. Systems like onion routing (TOR) and Freenet are presented. Knowledge in computer science and networking is needed, but no background in cryptography is expected.