​Advance topics in Cryptography; Authentication; Integrity; Key Distribution and Certification; Access Control: Firewalls; Attacks and Countermeasures: Mapping, Packet Sniffing, IP Spoofing, Denial-of-Service and Distributed Denial-of-Service Attacks, Hijacking; Security in Many Layers: HTTPS, Secure E-mail, Secure Sockets Layer (SSL) and Transport Layer Security (TLS), IPsec, Security in wireless networks such as IEEE 802.11, Mobile agents security.​