The course covers theory and practice of computer security, focusing in particular on the security aspects of the computer systems, Web and Internet. It introduces network and system security threats, then surveys cryptographic tools used to provide security, such as shared key encryption (DES, 3DES, RC-4/5/6, etc.); public key encryption, key exchange, and digital signature (Diffie- Hellmann, RSA, DSS, etc.). It then reviews how these tools are utilized in the internet protocols and applications such as Kerberos, SSL, IPSEC, TLS, PGP, S/MIME, SET, and others. System security issues, such as viruses, intrusion, firewalls, and others will also be covered.Aims:System and network security is becoming increasing important in networking. Malicious users such as hackers tend to keep above times and continuously compete against existing security mea- sures. The objective of the course is to introduce students to security threats and the methods to tackle them. The course shall focus on systems security for desktop and host computing devices as well as network security issues, which will equip student with fundamental techniques required for IT managers and system administrators.