Quiz-1

Q1. In Blockchain __________ tree stores all the transactions in a block by producing a hash of the entire set of transactions

• AVL

• Merkle

• Binary

• Red Black

Correct Answer : Merkle

Q2. Which of the following is not a blockchain component?

• Wallet

• Certificate Authority

• Ledger

• Cryptographic Hash

Correct Answer :Certificate Authority

Q3. Blockchain is a peer-to-peer _____________ distributed ledger technology that makes the records of any digital asset transparent and unchangeable

• Decentralized

• Demanding

• Secure

• Popular

Correct Answer : Decentralized

Q4. Who introduced the digital online cryptocurrency known as Bitcoin?

• Satoshi Nakamoto

• Nick Szabo

• Wei Dai

• Hal Finney

Correct Answer : Satoshi Nakamoto

Q5. What does a block in a Blockchain have?

• Header & Digital ledger

• Bitcoins & Input

• Transactions & Bitcoins

• Header & Transaction

Correct Answer : Header & Transaction

Q6. A genesis block is ____________

• Any block created by the founder

• The last block created in the Blockchain

• The first block of a Blockchain

• The first transaction in each block

Correct Answer : The first block of a Blockchain

Q7. __________ receive verify, gather and execute transactions

• Miner nodes

• Smart Contracts

• Light wallets

• Ether

Correct Answer : Miner nodes

Q8. Smart Contract characteristics do not include:

• Alterable

• Fast and cost-effective

• A high degree of accuracy

• Transparency

Correct Answer : Alterable

Q9. Hash identifying each block in the blockchain is generated using which of the following cryptographic algorithm

• SHA128

• SHA256

• Both

• None

Correct Answer : SHA256

Q10. Which of the following statement is true about blockchain?

• A blockchain is a decentralized, distributed, and oftentimes public, digital ledger consisting of records called blocks

• A blockchain database is managed autonomously using a peer-to-peer network and a distributed timestamping server

• A blockchain has been described as a value-exchange protocol

• All of the above

Correct Answer : All of the above

Q11. Which of the following statement is true about bitcoin?

• There is no central server; the bitcoin network is peer-to-peer

• There is no central storage; the bitcoin ledger is distributed

• The ledger is public; anybody can store it on their computer

• All of the above

Correct Answer :All of the above

Q12. The term used for Blockchain spilt is _____

• fork

• Merge

• division

• none of the above

Correct Answer : fork

Q13. The five elements of blockchain are distribution, encryption, immutability, tokenization and:

• Transparency

• Authorization

• Efficiency

• Decentralization

Correct Answer : Decentralization

Q14. Smart contracts are legally binding contracts

• TRUE

• FALSE

Correct Answer :TRUE

Q15. Which of the following industry can use blockchain technology for cybersecurity?

• Logistics

• Healthcare

• Critical Infrastructure

• All of the above

Correct Answer : All of the above

ASSIGNMENT-1

Q1. Which features distinguish databases from blockchain ledgers? Provide a comparative analysis of the two. 

• Databases and blockchain ledgers are both used to store and manage data, but they have some key differences in terms of features and functionality.

• One major difference is that databases are typically centralized, meaning that there is a single point of control and access. In contrast, blockchain ledgers are decentralized, with no single point of control or access. This decentralization is achieved through a distributed network of nodes that maintain copies of the ledger, and it makes blockchain ledgers more resistant to tampering or failure.

• Another key difference is that traditional databases use a single set of rules and protocols for data management, while blockchain ledgers use consensus algorithms to validate and record transactions. This means that blockchain ledgers are more secure and transparent, as every transaction is recorded and can be audited.

• In terms of data structure, databases are more flexible as they can use different data structures like relational, document-oriented, key-value, graph and time-series. Blockchain, on the other hand, primarily uses a linked-list data structure called blocks, which are chained together to form a chain, hence the name blockchain.

• Lastly, the data within a database can be edited, deleted or amended, but in a blockchain, once a block is added to the chain, it cannot be altered or deleted. This feature provides immutability to the data stored in a blockchain.

• In summary, databases and blockchain ledgers have different features, with databases being more centralized, flexible, and editable, while blockchain ledgers are decentralized, secure, transparent and immutable.

Q2. Explain how blockchain can be introduced in the education system to certify the credentials of candidate teachers and ascertain the security of the pupils’ personal data. 

Blockchain technology can be introduced in the education system to certify the credentials of candidate teachers and secure the personal data of pupils in several ways:

• Credential verification: Blockchain can be used to create a secure and tamper-proof digital record of a teacher's qualifications and certifications. This can include their degrees, teaching licenses, and other relevant credentials. This information can be stored on the blockchain and can be accessed by schools and educational institutions to verify the qualifications of a candidate teacher quickly and easily.

• Secure data storage: Blockchain can be used to securely store and manage personal data of pupils such as grades, attendance records, and other sensitive information. The decentralized nature of blockchain ensures that the data is secure and can only be accessed by authorized parties.

• Digital Identity Management: Blockchain can be used to create a unique digital identity for each student that is stored on the blockchain. This would allow for secure and private access to personal data and credentials, and can also be used to verify the identity of students when they are taking exams or other assessments.

• Enhancing transparency: Blockchain can be used to create a transparent and tamper-proof record of all educational activities, such as attendance, grades, certifications, and other achievements. This can help in creating a fair and unbiased system, as every record can be audited and tracked.

• Decentralized and Automated Record Keeping: With the implementation of blockchain, the education system can have a decentralized and automated record keeping system. This eliminates the need for intermediaries and reduces the cost of record keeping.

By implementing blockchain technology in the education system, it can provide a secure, transparent, and efficient way to manage the personal data of pupils, and verify the credentials of candidate teachers.

Q3. How does blockchain technology prevent/ solve the problem of “Double spending” in digital currencies such as Bitcoin? 

• Blockchain technology prevents the problem of "double spending" in digital currencies like Bitcoin by using a consensus mechanism called "Proof of Work" (PoW).

• In traditional digital currency systems, a digital token can be copied and spent multiple times, resulting in the problem of "double spending". However, in a blockchain network, each transaction is grouped with other transactions into a "block" and added to the existing chain of blocks, called the "blockchain".

• When a new block is added to the blockchain, it must be validated by the network's nodes through a complex mathematical problem, known as the PoW. This problem can only be solved by a node that expends significant computational power, and the solution is called a "hash". The first node that solves the PoW problem and generates the correct hash, is allowed to add the block to the blockchain, and this node is rewarded with a small amount of the digital currency.

• Once a block is added to the blockchain, it cannot be altered or deleted, and the information it contains becomes a permanent part of the blockchain. This means that once a digital token is spent, the transaction is recorded on the blockchain, and the same token cannot be spent again.

• In summary, the use of the consensus mechanism of PoW, where every transaction is grouped into blocks, and added to the blockchain, in a decentralized way, through a complex mathematical problem, solved by nodes, ensures that every digital token can only be spent once, preventing the problem of double-spending.

Q4. Suggest which type of blockchain should be used for the security of donations in a charity organization. What benefits does the blockchain technology introduce in such a scenario? Explain your answer using an example. 

For the security of donations in a charity organization, a public blockchain would be the most suitable. Public blockchains are decentralized and open to anyone, allowing for transparency and immutability of transactions.

Benefits that blockchain technology can bring to a charity organization include:

1. Transparency: Public blockchains allow for complete transparency of transactions, allowing donors to see exactly where their money is going and how it is being used.

2. Immutability: Once a transaction is recorded on the blockchain, it cannot be altered or deleted, providing a permanent record of donations.

3. Decentralization: Public blockchains are decentralized, meaning that there is no single point of control or access, providing security and reducing the risk of fraud.

4. Traceability: With the use of blockchain, it is possible to trace the path of a donation from the donor to the recipient, ensuring that the funds reach the intended party.

Q5. Analyse, using a diagram, how a distributed ledger works, present its main characteristics, and explain how it differs from a “traditional” centralized ledger.

A distributed ledger is a type of database that is spread across a network of computers, rather than being stored in a single location.

Here is a diagram that illustrates how a distributed ledger works:

[Diagram of a distributed ledger]

• Transactions are initiated by a user and broadcast to the network.

• Transactions are grouped together into a block and added to the existing chain of blocks, called the "blockchain".

• Each block contains a unique code, called a "hash", that links it to the previous block.

• Each node in the network maintains a copy of the ledger, and the consensus mechanism ensures that all copies of the ledger are identical.

• Once a block is added to the blockchain, it cannot be altered or deleted, providing a permanent record of transactions.

The main characteristics of a distributed ledger are:

• Decentralization: There is no single point of control or access, meaning that the ledger is spread across a network of computers.

• Immutability: Once a block is added to the blockchain, it cannot be altered or deleted, providing a permanent record of transactions.

• Transparency: All transactions are recorded on the blockchain, allowing for complete transparency.

• Security: The use of cryptographic techniques and consensus mechanisms ensures that the ledger is secure and resistant to tampering.

A traditional centralized ledger, on the other hand, is stored in a single location and controlled by a central authority. It is more vulnerable to tampering and failure and less transparent than a distributed ledger. A centralized ledger system is not as secure as a distributed ledger, and the data stored within is not as transparent. Transactions are not as transparent, as the data is controlled by a central authority, who might not disclose all the information.

In summary, a distributed ledger works by spreading the storage and management of data across a network of computers, providing decentralization, immutability, transparency, and security. It differs from a traditional centralized ledger in that it is not controlled by a central authority, and it is more secure, transparent and resistant to tampering.