Tor Network

📘 Tor Network — Exam Notes (Network Security)

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🧅 1. Definition

The Tor Network (The Onion Router) is a free, decentralized network that enables anonymous communication over the internet by routing traffic through multiple encrypted layers of nodes.

👉 Simple idea: Tor hides a user’s identity by sending data through a series of encrypted “relay points”, making it difficult to trace the original source.

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🎯 2. Objectives of Tor Network

• Provide anonymous internet browsing
• Hide user IP address
• Protect privacy and location
• Prevent tracking and surveillance
• Enable access to restricted content

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🧠 3. Why “Onion Routing”?

Tor uses a method called Onion Routing because:

• Data is wrapped in multiple layers of encryption
• Each relay removes one layer (like peeling an onion)
• Final destination is reached without revealing the source

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🔄 4. How Tor Works

Step-by-step process:

1. User connects to Tor Browser

2. Data is encrypted multiple times

3. Traffic passes through a chain of nodes:

   • Entry Node
   • Middle Relay
   • Exit Node

4. Each node decrypts only one layer

5. Exit node sends data to destination

👉 Important: No single node knows both source and destination.

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🧱 5. Components of Tor Network

🔹 1. Tor Client (User)

• Uses Tor Browser
• Starts encrypted communication

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🔹 2. Entry Node (Guard Node)

• First point in Tor network
• Knows user IP but not destination

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🔹 3. Middle Relay Node

• Passes data forward
• Does not know source or destination

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🔹 4. Exit Node

• Final node before internet
• Sends data to target website
• Can see destination but not user identity

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🔐 6. Security Features of Tor

• Multi-layer encryption (Onion routing)
• IP address masking
• Decentralized architecture
• No single point of control
• Strong anonymity

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⚠️ 7. Limitations of Tor Network

• Slow browsing speed
• Exit node can see unencrypted traffic
• Not fully anonymous if misused
• Some websites block Tor users
• Can be used for illegal activities

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🛡️ 8. Tor vs VPN

Feature	Tor	VPN
Privacy	Very high	High
Speed	Slow	Fast
Encryption	Multi-layer	Single tunnel
Traceability	Very difficult	Possible by provider
Use case	Anonymous browsing	Secure browsing

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📊 9. Important Concept

🔸 Onion Routing Principle

Data = Multiple Encryption Layers → Each Node Removes One Layer → Anonymous Communication

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🖼️ 10. Diagram Descriptions

📌 Tor Network Flow

• User → Entry Node → Middle Node → Exit Node → Website

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📌 Onion Layers

• Data wrapped in multiple encryption layers

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📌 Anonymous Routing

• Source hidden from destination

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🧾 11. Real-Life Examples

• 🕵️ Journalists communicating securely
• 🌐 Users bypassing censorship
• 🔐 Whistleblowers sharing information anonymously
• 🧪 Researchers studying privacy systems

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📝 Likely Exam Questions

1. Define Tor Network.
2. Explain Onion Routing.
3. Describe working of Tor Network.
4. What are the components of Tor?
5. Differentiate between Tor and VPN.
6. What are entry, middle, and exit nodes?
7. What are advantages and disadvantages of Tor?
8. Why is Tor called onion routing?
9. Is Tor completely secure? Explain.
10. Write short notes on:

• Exit node
• Anonymity
• Tor Browser

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📌 Quick Summary / Conclusion

• The Tor Network provides anonymous communication over the internet.
• It uses onion routing with multiple encrypted layers.
• Traffic passes through entry, middle, and exit nodes.
• It hides user identity but may reduce speed and has some limitations.

👉 In short: Tor is a privacy-focused network that hides user identity by routing data through multiple encrypted nodes, ensuring anonymity online.

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