Protection & Security in Operating Systems

Introduction
In the digital world, operating systems (OS) act as the foundation for secure computing. Protection and security are crucial aspects of an OS, safeguarding its resources and ensuring seamless, reliable operation.

Understanding the Terms

Protection: refers to controlling access and usage of system resources (CPU, memory, disk, etc.) by processes and users. It focuses on internal threats, preventing interference and errors caused by unauthorized access or program malfunction.
Security: encompasses broader aspects, protecting the OS from external threats like malware, hackers, and unauthorized physical access. It ensures the system's confidentiality, integrity, and availability (CIA triad):
Confidentiality: Data should be accessible only to authorized users.
Integrity: Data and system resources should remain unaltered and consistent.
Availability: Authorized users should have uninterrupted access to system resources.

Protection Mechanisms

User Authentication: Mechanisms like usernames/passwords, biometrics, or multi-factor authentication verify user identity before granting access.
Resource Access Control: Access permissions define which users and programs can access specific resources (files, devices, etc.).
Memory Management: Techniques like memory isolation and virtualization prevent processes from interfering with each other's memory space.
System Integrity Protection: Features like code signing and secure boot verify the authenticity and integrity of system software.

Security Measures

Firewall: Monitors incoming and outgoing network traffic, blocking unauthorized access attempts.
Anti-malware Software: Detects and removes malware like viruses, worms, and trojans.
System Updates: Regular updates patch vulnerabilities and address security flaws.
Physical Security: Measures like access control lists and surveillance cameras prevent unauthorized physical access to the system.

Goals of protection

In one protection model, computer consists of a collection of objects, hardware or software.
Each object has a unique name and can be accessed through a well defined set of operations.
Protection problem - ensure that each object is accessed correctly and only by those processes that are allowed to do so.

Security Violation Categories

Breach of confidentiality - Unauthorized reading of data.
Breach of Integrity - Unauthorized modification of data.
Breach of Availability - Unauthorized destruction of data.
Theft of Service - Unauthorized use of resources.
Denial of Service(DOS) - Prevention of legitimate use.

Key Points

Protection and security are essential for reliable and secure computing.
They address both internal and external threats.
The CIA triad (confidentiality, integrity, and availability) serves as a guiding principle.
Various mechanisms and measures work together to achieve protection and security.

Further Exploration

Explore specific protection and security features in different operating systems (Windows, Linux, macOS).
Research emerging security threats and how OSes adapt to combat them.
Understand the role of encryption in secure communication and data storage.