Operating System
OS Part-1
OS Part-2
- File Concepts and Access methods
- Free Space Management and Allocation methods
- Directory Systems and Protection
- File Organization, Sharing and Implementation issues
- Disk and Drum Scheduling
- I/O Devices Organisation & I/O Buffering
- I/O Hardware, Kernel I/O subsystem and Transforming I/O Requests to Hardware Operations
- Device Drivers and Path Management
- Device Driver Sub Modules and Procedure
- Device Scheduler and Handler
- Interrupt Service Routine (ISR)
- File System in Linux and Windows
OS Part-3
- Process and Process Control Block(PCB)
- Process Scheduling( Preemptive and Non Preemptive)
- Scheduling Algorithms
- Algorithm Evaluation
- Multiple Processor Scheduling
- Real Time Scheduling
- Operations on Processes
- Threads
- Inter-Process Communication
- Precedence Graphs
- Critical Section Problem
- Semaphores
- Classical Problems of Synchronization
- DeadLock
- Deadlock Prevention and Avoidance
- Deadlock Detection and Recovery
- Process Management in Linux
OS Part-4
- Memory Hierarchy in OS
- Concepts of Memory Management
- MFT and MVT
- Logical and Physical Address Space
- Swapping
- Contiguous and Non Contiguous Memory Allocation
- Paging
- Segmentation
- Paging Combined with Segmentation
- Structure and Implementation of Page Table
- Virtual Memory in OS
- Cache Memory Organization
- Demand Paging
- Page Replacement Algorithms
- Allocation of Frames and Thrashing
- Demand Segmentation
OS Part-5
- Distributed Operating System: Introduction and Types
- Distributed OS: Design Issues
- Distributed OS: File System
- Distributed OS: Remote File Access
- Remote Procedure Call(RPC)
- Remote Method Invocation(RMI)
- Distributed Shared Memory
- Parallel Processing and Concurrent Programming
- Security and Threats Protection in Distributed OS
- Security Design Principles and Authentication in Distributed OS
- Sensor Network and Parallel OS
Security Design Principles & Authentication in Distributed Operating System
Distributed Operating System (DOS) me security ek important aspect hota hai kyunki multiple devices network ke through connected hote hain. Is wajah se unauthorized access, data breaches, aur malware attacks ka risk hota hai.
Is explanation me hum Security Design Principles aur Authentication Mechanisms ke baare me detail me samjhenge, diagrams aur examples ke saath.
Security Design Principles in Distributed OS
Security design principles secure system design ke liye guidelines provide karte hain.
Key Security Design Principles
1. Least Privilege
Kisi user ya process ko sirf utni hi access di jaye jitni zaroori ho.
Example:
Ek banking system me teller sirf customer ke account balance check kar sakta hai, money transfer nahi.
2. Defense in Depth
Multiple security layers ka use karna taaki agar ek layer breach ho to doosri layer protection provide kare. Example: Firewall + Antivirus + Encryption ka ek sath use karna.
3. Fail-Safe Defaults
Default access policy “Deny” hoti hai. Jab tak explicitly permission na di jaye, access nahi milega. Example: Ek server me by default kisi bhi naye user ko restricted access diya jata hai jab tak admin permission na de.
4. Economy of Mechanism
Security mechanisms jitne simple honge, utne hi zyada effective honge. Example: Complex authentication systems me bugs hone ke chances badh jate hain, isliye simple password-based authentication + OTP better hota hai.
5. Open Design
Security system secret algorithms pe depend nahi karta, balki strong encryption aur secure keys ka use karta hai. Example: AES Encryption ek publicly known algorithm hai par phir bhi secure hai kyunki encryption keys secret hoti hain.
6. Complete Mediation
Har request ko re-check kiya jaye ki user abhi bhi authorized hai ya nahi. Example: Ek website me agar user login timeout hone ke baad request bhejta hai, to system usse dobara authenticate karega.
7. Separation of Privileges
Ek action perform karne ke liye multiple approvals ki zaroorat hoti hai. Example: Ek financial transaction approve karne ke liye dono manager aur accountant ka approval chahiye.
8. Least Common Mechanism
Shared resources ka minimum use ho taaki attackers ko kam attack points milein. Example: Ek multi-user system me har user ka separate memory allocation hota hai taaki ek user doosre ka data access na kar sake.
9. Psychological Acceptability
Security easy to use honi chahiye, taaki users security measures ko bypass na karein. Example: Agar password reset process bahut complex ho, to users weak passwords use karne lagte hain.
Authentication in Distributed OS
Authentication ka matlab hai verify karna ki user ya process jo claim kar raha hai, wahi hai ya nahi.
Authentication Techniques
1. Password-Based Authentication
User username + password ka use karta hai. Example: Gmail ya Facebook me email + password enter karke login karna.
Issue: Weak passwords easily guess ho sakte hain.
2. Multi-Factor Authentication (MFA)
Password + OTP + Biometric ka combination use hota hai. Example: Online banking password + OTP maangta hai.
3. Biometric Authentication
Fingerprint, Face Recognition, Retina Scan ka use hota hai. Example: Smartphone unlocking using fingerprint sensor.
4. Token-Based Authentication
User ko authentication token (OTP, Smart Card, USB Key) diya jata hai. Example: Google Authenticator App jo temporary login codes generate karta hai.
5. Kerberos Authentication Protocol
Distributed Systems me secure authentication ke liye use hota hai. Ye password ko network pe transmit nahi karta, balki tickets ka use karta hai.
Working:
-
User login request send karta hai.
-
Server encrypted ticket generate karta hai.
-
User jab bhi access request karega, ticket validate kiya jayega.
Diagram: Kerberos Authentication
Is model me password directly transmit nahi hota jo security badhata hai.
Secure Authentication Model in Distributed OS
Ek secure authentication model ka structure kuch is tarah hota hai:
Diagram: Secure Authentication Model
Ye model ensure karta hai ki only authorized users secure resources access karein.
Conclusion
Security Design Principles help karte hain ek secure distributed system design karne me. Authentication methods (Password, MFA, Kerberos, Biometric) use karke system ko unauthorized access se protect kiya jata hai. Secure authentication models ka use distributed systems me security badhane ke liye hota hai.