Introduction, computer network architectures, attacks to networks, security services and mechanisms. Cryptographic tools, user authentication, access control, malware, denial of service attacks, intrusion detection, firewalls, attack prevention mechanisms. Symmetric encryption, Data Encryption Standard (DES), Advanced Encryption Standard (AES), multiple encryption, asymmetric algorithms, public key cryptography, RSA. Data integrity, hash functions, Secure Hash Algorithm (SHA), message authentication code (MAC), digital signatures. Authentication, Kerberos, X.509 standard, Public Key Infrastructure (PKI). Internet security, Secure Sockets Layer (SSL), Transport Layer Security (TLS), HTTPS, SSH. Wireless network security, IEEE 802.11i, transport layer security. E-mail security, Pretty Good Privacy (PGP), Secure Multipurpose Internet Mail Extensions (S/MIME), DomainKeys Identified Mail (DKIM). Laboratory exercises on encryption algorithms, vulnerability and intrusion detection, firewalls.