Conceptual foundations of Information Systems Security conditions . Access Control : MAC, DAC, RBAC. Security Models for Information Systems . Virus-like Software. Security and relevant Standards Measurement Systems . Details Applied Cryptography : Classical Cryptographic methods . Symmetric and asymmetric cryptosystems . Message Authentication Codes . Digital Signatures . Trusted Third Entities : user requirements , services , technology solutions , and maintenance policies of certificates , monitoring methods and evaluation techniques. Public Key Infrastructure .Applications in e-business environment . Privacy Protection: Directions in OECD and EU. Legislative framework in Greece . Network Security Issues : Categories Threat , Vulnerability Points , Countermeasures , Assurance . Network Security Architecture ISO / OSI: Security Services , Security Devices , Security Management. Security Architecture Model in the Internet: Layer Security Internet, Transport Layer Security , Application Layer Security , Safety above the application level . Benchmarking solutions . Applications. Electronic Security Gates : Architectures , Evaluation . Applications. Mobile code security model : Java, ActiveX, SafeTcl.Protection Technologies Privacy and Anonymity : Cookies, Anonymous Browsing, Anonymous Publishing. Censorship of Web technology . Systems Authentication in Distributed Environments . Secure Electronic Payment Systems . Analysis and Risk Management Information System : Methodologies and tools available .