Computer Security

Basic Components

Confidentiality

–Keeping data and resources hidden

•Integrity

–Data integrity (integrity)

–Origin integrity (authentication)

•Availability

–Enabling access to data and resources

Classes of Threats

Disclosure

–Snooping

•Deception

–Modification, spoofing, repudiation of origin, denial of receipt

•Disruption

–Modification

•Usurpation

–Modification, spoofing, delay, denial of service

Policies and Mechanisms

•Policy says what is, and is not, allowed

–This defines “security” for the site/system/etc.

•Mechanisms enforce policies

•Composition of policies

–If policies conflict, discrepancies may create security vulnerabilities

Goals of Security

•Prevention

–Prevent attackers from violating security policy

•Detection

–Detect attackers’ violation of security policy

•Recovery

–Stop attack, assess and repair damage

–Continue to function correctly even if attack succeeds