Tanım: Operating system and computer network security basics, risk analysis, security policies, concept of trusted computers and networks. Conventional and public key cryptography. Authentication and digital signatures. Authentication protocols and applications, Kerberos, certificates. UNIX/LINUX security issues. IP, TCP/UDP, SSL, DNS, FTP/TELNET, NIS/NFS, SNMP electronic mail and web security. Firewalls and security tools. Secure payment systems. Case studies and programming projects.