Introduction and course overview, overview of security; introduction to cryptography, Security notions for private-key encryption, Private-key encryption schemes, modes of encryption, Basic number theory, public-key encryption, RSA, RSA, generating random primes, El Gamal encryption, hybrid encryption, 30 Message integrity, message authentication codes, signature schemes, Signature schemes, hash functions, PKI, Access control, Security policies, Security policies: confidentiality, integrity, Integrity policies, access control, Access control, design principles, computer viruses/worms, Authentication, passwords, Authentication protocols, protocols for network security.