IB Year 2 Standard Level Computer Science

Monday 3 February 2025 - Block 5

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There are about 4 months and 26 days until school ends. How are you going to use that time to make sure you do your best?

Daily Note

Hello.

I'll be out the rest of the week. We do not have the luxury of waiting, so we need to start learning about our next unit in web science, distributed approaches to the web. Your test on search will happen when I come back. 

Today we will learn about Decentralization of the web

1. Please scan through this wiki page.
2. Please make sure you can clearly define decentralization of the web
3. This topic can be very confusing! Carefully, carefully read the top paragraph on our wiki.
4. Please complete the quiz below and check out the markscheme but not before you have tried your work:

Quiz: Decentralization of the Web

1. Define the term "Decentralization of the Web" and provide one example of a technology that enables it. (2 marks)

2. Compare centralized and decentralized web models in terms of control, data storage, and censorship resistance. (6 marks)

3. Explain how peer-to-peer (P2P) networks contribute to the decentralization of the web. (4 marks)

4. Discuss the impact of blockchain technology on privacy and security in decentralized web systems. (6 marks)

5. Evaluate the challenges and limitations of a fully decentralized web, considering factors such as scalability, regulation, and user experience. (8 marks)

 

 

 

Markscheme: Decentralization of the Web Quiz

 

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1. Define the term "Decentralization of the Web" and provide one example of a technology that enables it. (2 marks)

Mark Allocation:

• 1 mark for an accurate definition of "Decentralization of the Web."
  • Example: "Decentralization of the web refers to the distribution of control, data, and computational resources across multiple nodes rather than being managed by a single centralized authority."
• 1 mark for a valid example of a technology that enables decentralization.
  • Acceptable examples: Blockchain, IPFS, Peer-to-Peer (P2P) networks, Decentralized Autonomous Organizations (DAOs), Cryptographic tools, etc.

✖ No marks if the definition is incorrect or missing, or if the example does not relate to decentralization.

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2. Compare centralized and decentralized web models in terms of control, data storage, and censorship resistance. (6 marks)

Mark Allocation:

• 1 mark per correctly stated comparison (maximum 6 marks).
• Students must cover all three aspects (control, data storage, censorship resistance).

Aspect	Centralized Web	Decentralized Web
Control	Controlled by a single entity (e.g., Google, Facebook)	Distributed across multiple participants
Data Storage	Stored in centralized servers owned by companies	Stored across a distributed network
Censorship Resistance	Platforms can remove content, users can be banned	Harder to censor due to data spread across multiple nodes

• 2 marks for correctly explaining control in both centralized and decentralized web models.
• 2 marks for correctly explaining data storage in both models.
• 2 marks for correctly explaining censorship resistance in both models.

✖ No marks for vague statements like "Decentralized is better than centralized." Answers must explicitly compare both models for each aspect.

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3. Explain how peer-to-peer (P2P) networks contribute to the decentralization of the web. (4 marks)

Mark Allocation:

• 1 mark for stating what a P2P network is.
  • Example: "A peer-to-peer (P2P) network is a system where computers (nodes) communicate directly with each other without relying on a central server."
• 1 mark for explaining how P2P networks distribute data.
  • Example: "In a P2P network, data is stored across multiple devices, reducing reliance on a single entity."
• 1 mark for explaining how P2P networks reduce censorship.
  • Example: "Since data is stored on multiple devices, no single authority can remove or block access to it."
• 1 mark for explaining how P2P networks improve resilience/security.
  • Example: "P2P networks are more resilient to attacks because data is distributed, making it harder to disrupt the entire network."

✖ No marks for simply stating "P2P makes the web decentralized" without further explanation.

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4. Discuss the impact of blockchain technology on privacy and security in decentralized web systems. (6 marks)

Mark Allocation:

• 1 mark for defining blockchain technology.
  • Example: "Blockchain is a distributed ledger technology that records transactions across multiple nodes, ensuring transparency and immutability."
• 2 marks for explaining how blockchain improves privacy.
  • Example: "Blockchain enables anonymous transactions through cryptographic hashing and decentralized identity management."
  • Example: "Users retain control of their personal data without relying on third-party verification."
• 2 marks for explaining how blockchain enhances security.
  • Example: "Blockchain transactions are immutable and verified through cryptographic consensus, making them resistant to hacking."
  • Example: "Decentralization reduces the risk of a single point of failure, preventing large-scale breaches."
• 1 mark for acknowledging potential security/privacy challenges (e.g., public ledger visibility, 51% attacks).

✖ No marks for vague statements like "Blockchain is secure and private" without explanation.

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5. Evaluate the challenges and limitations of a fully decentralized web, considering factors such as scalability, regulation, and user experience. (8 marks)

Mark Allocation:

• 1 mark for defining decentralization.
• 2 marks for discussing scalability challenges.
  • Example: "Decentralized networks require significant computing power and bandwidth, making them harder to scale than centralized solutions."
• 2 marks for discussing regulation/legal challenges.
  • Example: "Governments may impose restrictions on decentralized networks, such as banning cryptocurrencies or regulating decentralized services."
• 2 marks for discussing user experience challenges.
  • Example: "Many decentralized platforms require technical knowledge, which can limit accessibility for non-technical users."
• 1 mark for a conclusion that weighs the benefits vs. challenges (e.g., "While decentralization enhances privacy and security, challenges like scalability and regulation must be addressed for widespread adoption.").

✖ No marks for one-sided arguments that only list benefits or only list challenges without evaluation.

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Total Marks: 26

 

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Reminders & routines:

Please read and follow these reminders:

1. IF today == Friday:
       careers_in_computing()

 

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