ITCS 422: Distributed Systems & Multimedia: (3-0-3) This course provides introduction to both theory and practice of data security. The theory part includes conventional crypto-algorithms, public-key crypto-algorithms, hash functions and digital signatures. The practice part covers important data security tools and applications: Kerberos, SSH, X.509, IP Security, SSL/TLS, and possibly others. This course is self-contained: basic mathematical foundations,