BLOCKCHAIN TECHNOLOGY QUESTION BANK

1. What is Blockchain Technology? What are the various application areas of Blockchain Technology? (Or) Use-cases
of Blockchain Technology

Blockchain Technology is a decentralized, distributed digital ledger technology that records transactions
securely and transparently across a peer-to-peer network. It was initially introduced as the foundational
technology for Bitcoin by Satoshi Nakamoto in 2008 but has since evolved beyond digital currency
applications. Blockchain ensures that data, once recorded, is immutable, secure, and verifiable without
needing a trusted third party.

Key Features:

 Decentralization: Blockchain operates without a central authority, allowing distributed data across
nodes.

 Transparency: Transactions are visible to all participants in the network, promoting accountability.

 Immutability: Once recorded, data cannot be altered, adding security to the network.

Application Areas:

1. Cryptocurrency Transactions: Blockchain is the backbone of cryptocurrencies like Bitcoin, enabling peer-
to-peer currency transfer without intermediaries.

2. Data Storage: Blockchain stores data securely for sectors needing high data integrity, such as healthcare
for medical records.

3. Supply Chain Management: Tracks goods throughout their lifecycle, improving transparency in
industries like food and pharmaceuticals.

4. Voting Systems: Blockchain can create secure, tamper-resistant voting platforms, ensuring each vote’s
validity and traceability.

5. Property and Asset Transactions: Allows digital representation of assets, including real estate, vehicles,
and intellectual property, for verifiable transfer.

2. Write Short Notes / Short Answer Questions

1. Shared ledger

2. Permissions

3. Consensus

4. Smart contracts

5. Mining Pools

6. Hashcash

 Shared Ledger: A blockchain network’s shared, distributed ledger records transactions securely
and is accessible to all authorized participants. It is cryptographically secured, ensuring data
authenticity and integrity.

 Permissions: Permissions define access control within a blockchain network. In public

blockchains, anyone can join and participate, while private or permissioned blockchains restrict
access to selected participants, often with known identities, ensuring controlled participation.

 Consensus: The process by which nodes in a blockchain network agree on a single data value or
state of the ledger, ensuring consistency across the network. Examples include Proof of Work
 (PoW) and Proof of Stake (PoS), used to validate transactions and ensure trust without central
authority.

 Smart Contracts: Self-executing contracts where the terms are directly written into code. They
automatically execute actions when predefined conditions are met. Commonly used on platforms
like Ethereum, smart contracts facilitate decentralized applications (dApps) across finance, supply
chain, and legal sectors.

 Mining Pools: Groups of miners who combine computational resources to increase their chances
of finding new blocks. By pooling resources, miners earn rewards more consistently, sharing the
profits based on their contributions.

 Hashcash: A proof-of-work system used to prevent spam and denial-of-service (DoS) attacks by
requiring a computational effort to generate a valid transaction. Initially developed for email spam
prevention, it was later adapted by Bitcoin to secure the network.

3. Draw and explain the Blockchain NETWORK.

A blockchain network operates through a series of layers stacked on top of the internet:

 Layer 1: Internet Communication: Forms the base, allowing nodes to connect and share information.

 Layer 2: Peer-to-Peer Network: Enables decentralized interactions among nodes, each having a copy of
the blockchain ledger.

 Layer 3: Blockchain Protocol: Contains the transactions, blocks, and consensus mechanisms that validate
and verify actions.

 Layer 4: Applications and Smart Contracts: The top layer, where decentralized applications (dApps) run
and interact with users.

In practice, a block is composed of transaction data, a timestamp, and a cryptographic hash linking it to
the previous block. Miners, or validating nodes, use consensus mechanisms to confirm transactions,
which then become permanent entries in the blockchain.

4. Explain the emergence of Bitcoin (Or) Explain the birth of blockchain along with the history of blockchains.

The concept of blockchain began in 1991, intended to timestamp documents to prevent tampering.
However, the breakthrough came in 2008 when Satoshi Nakamoto introduced Bitcoin, a digital currency
built on blockchain, through a white paper titled "Bitcoin: A Peer-to-Peer Electronic Cash System."
Nakamoto’s design allowed secure peer-to-peer transactions, solving the double-spending problem via
decentralized consensus.
 Bitcoin’s success led to blockchain’s wider adoption beyond digital currency, as its decentralized,
transparent, and immutable qualities showed potential across multiple industries. The invention of
Ethereum in 2015 expanded blockchain’s capabilities by introducing smart contracts, allowing the
automation of complex processes.

5. Explain all the different types of blockchains

1. Distributed Ledgers

A Distributed Ledger is a broad term encompassing databases that are distributed across multiple sites,
countries, or institutions. Unlike traditional databases, a distributed ledger does not rely on a central
administrator; instead, data is shared, replicated, and synchronized among all participants. Distributed
ledgers store transaction records in a decentralized way, ensuring security and reducing the risk of a
single point of failure. While all blockchains are distributed ledgers, not all distributed ledgers use
blockchain structures.

Key Features:

 Decentralized Storage: Data is not stored in a single central location but is spread across various nodes.

 High Security: Distributed ledgers are inherently more secure as they rely on cryptographic techniques.

 Improved Data Integrity: Since data is synchronized across multiple locations, changes are tracked across
the network.

Examples:

 Ripple: Used in banking for cross-border payments without relying on centralized intermediaries.

 Corda: Specifically designed for financial services with a focus on privacy.

1. Public Blockchains

Public blockchains are decentralized, permissionless networks open to anyone who wants to participate.
In these blockchains, any individual can join as a node, read or write data, and take part in the consensus
process without needing permission. Public blockchains are highly transparent and secure due to their
decentralized nature and are primarily used in cryptocurrencies like Bitcoin and Ethereum.

Key Features:

 Open Participation: Anyone can join, making it completely decentralized.

 Transparent Transactions: All transactions are visible, ensuring accountability.

 Consensus Mechanism: Commonly use Proof of Work (PoW) or Proof of Stake (PoS) to achieve
consensus.

Examples:

 Bitcoin: The first and most prominent public blockchain, primarily used for cryptocurrency transactions.

 Ethereum: Not only for cryptocurrency but also supports smart contracts, enabling decentralized
applications (dApps).

2. Private Blockchains

Private blockchains are permissioned networks, meaning access is restricted and participants need
permission to join. They are usually managed by a single entity or a consortium, allowing greater control
 over who can participate in the network, view transactions, and modify the ledger. This makes private
blockchains faster and more efficient but reduces their level of decentralization.

Key Features:

 Restricted Access: Only authorized participants can join the network.

 Faster Transactions: Due to fewer participants and controlled permissions, transactions are processed
more quickly.

 Enhanced Privacy: Since access is limited, the blockchain can be tailored for data privacy and
confidentiality.

Examples:

 Quorum: Developed by JPMorgan, it is based on Ethereum and designed for private use, especially
within financial institutions.

 Hyperledger Fabric: An open-source blockchain platform under the Linux Foundation, used primarily by
businesses requiring a private and permissioned network.

3. Semi-Private / Consortium (or Federated) Blockchains

Consortium blockchains, also known as federated blockchains, are semi-decentralized. They are
controlled by a group of organizations rather than a single entity, with permissions shared among pre-
selected nodes. These blockchains are popular among enterprises that want to collaborate and share
data without exposing sensitive information to the public. A consortium blockchain is more decentralized
than a private blockchain but not as open as a public one.

Key Features:

 Multi-Party Control: Several organizations control the network instead of a single authority.

 Efficiency: Generally faster than public blockchains due to limited participants and controlled
permissions.

 Shared Access and Responsibility: Members of the consortium are known, and the blockchain can
enforce selective visibility and access rights.

Examples:

 Hyperledger: A consortium blockchain often used in industries like healthcare, finance, and supply
chains, where multiple stakeholders need to share data.

 Corda: Designed for financial institutions, Corda facilitates secure and transparent transactions across
trusted parties.

4. Sidechains

Sidechains are independent blockchains that operate alongside a main blockchain (referred to as the
parent or mainnet) and are often used for scalability and specialized functionalities. Sidechains are
connected to the main blockchain through a two-way peg mechanism, allowing assets to be transferred
back and forth between the sidechain and the main chain. They allow the main chain to offload certain
tasks, like processing complex transactions or experimenting with new features, without compromising
security.

Key Features:

 Interoperability with Main Blockchain: Assets can be moved between the main chain and the sidechain.
 Enhanced Scalability: Allows for faster transactions and different consensus mechanisms suited for
specific tasks.

 Experimental Space: Provides a platform for testing new features without risking the security of the
main blockchain.

Examples:

 Liquid Network: A Bitcoin sidechain used for fast, private transactions, particularly suited for traders who
need quicker settlement times.

 Rootstock (RSK): A Bitcoin sidechain that enables smart contracts, adding Ethereum-like capabilities to
the Bitcoin network.

5. Permissioned Ledgers

A permissioned ledger is a type of blockchain where all participants are known and trusted by a central
authority or a consortium of entities. Permissioned blockchains don’t rely on a decentralized consensus
mechanism (like PoW) but instead use a protocol where preselected nodes validate transactions. This
makes permissioned blockchains efficient for enterprises that want more control over their data and
require higher transaction throughput and data confidentiality.

Key Features:

 Access Control: Nodes are preselected and trusted, bypassing the need for consensus through mining or
staking.

 High Performance and Efficiency: Optimized for fast processing as consensus is quicker due to limited
participants.

 Enhanced Data Privacy: Allows for tighter control over data access, making it suitable for sensitive
applications.

Example:

 Ripple: A permissioned ledger primarily used for real-time gross settlement and cross-border payments.

6. Tokenized Blockchains vs. Tokenless Blockchains

 Tokenized Blockchains: These blockchains generate cryptocurrency or tokens as part of the consensus
process or initial distribution, allowing participants to trade, store value, or interact with applications.
Examples include Bitcoin and Ethereum, where tokens (BTC, ETH) serve as a means of exchange and fuel
for transactions or applications on the blockchain.

 Tokenless Blockchains: Unlike tokenized blockchains, tokenless blockchains do not generate

cryptocurrency or tokens. They are designed primarily for data-sharing and record-keeping among
trusted participants without the need for a medium of exchange. They’re useful in cases where value
 transfer isn’t required, like within an organization needing secure, tamper-proof data sharing. Examples
include some implementations within Hyperledger Fabric.

7. One-Way Pegged Side Chains

One-Way Pegged Side Chains allow assets to move from a main blockchain to a sidechain but not back
again. This one-way transfer is achieved through a process known as Proof of Burn or a similar
mechanism. Coins or tokens are "burned" or rendered unspendable on the main blockchain and become
available on the sidechain. This technique is often used to create new alternative cryptocurrencies or
experimental systems that don’t require the asset to return to the main chain.

Key Features:

 Single-Direction Transfer: Assets are transferred from the main chain to the sidechain, with no return
option.

 Value Control: Limits the total supply on the main blockchain, creating scarcity and enhancing value.

 Useful for New Token Creation: Often used to bootstrap new tokens or alternative crypto projects.

Examples:

 Slimcoin: Uses a one-way peg where coins are permanently "burned" to generate new tokens on
another platform.

4. Two-Way Pegged Side Chains

Two-Way Pegged Side Chains allow assets to be transferred back and forth between the main chain and
sidechain, providing greater flexibility. In two-way pegs, assets are locked on the main chain and issued
on the sidechain. Users can move assets to a sidechain for faster transactions, additional privacy, or
smart contract capabilities and then return them to the main chain when done. This mechanism enables
scalability and adds unique functionalities to the main blockchain without risking its security.

Key Features:

 Bidirectional Transfer of Assets: Users can transfer assets between main and sidechains as needed.

 Increased Flexibility and Scalability: Sidechains can handle specific tasks like faster transactions or
experimental features without affecting the main blockchain.

 Supports Smart Contracts and New Features: Allows main chains, like Bitcoin, to leverage advanced
capabilities (e.g., smart contracts) through sidechains.

Examples:

 Rootstock (RSK): A two-way pegged sidechain of Bitcoin that brings Ethereum-like smart contract
functionality to Bitcoin.

 Liquid Network: A Bitcoin sidechain designed for fast, private transactions, particularly for institutional
traders.

5. Shared Ledgers

A Shared Ledger is a term used for any application or database shared by multiple parties. Shared
ledgers allow for collaborative environments where participants can access and verify the same data,
ensuring authenticity and consistency across the network. Unlike permissionless blockchains, shared
ledgers often exist in specific private or permissioned settings within organizations. These ledgers are not
necessarily blockchain-based but use state replication and agreement protocols to reach a consensus
among participants.
 Key Features:

 Collaborative and Controlled: Used within or among organizations to maintain a consistent view of
shared data.

 No Complex Consensus Needed: Often uses simple state replication with known validators, as opposed
to PoW or PoS.

 Useful in Private and Consortium Blockchains: Frequently employed within permissioned or

consortium-based blockchain solutions.

Examples:

 Supply Chain Networks: Shared ledgers can track and authenticate asset movement across different
points of the supply chain, where data transparency is key.

 Government Records: Allows secure and shared data access between departments, improving accuracy
in public records management.

6. Explain CAP Theorem

The CAP Theorem states that a distributed system cannot achieve Consistency, Availability, and
Partition Tolerance simultaneously:

1. Consistency (C): Ensures that all nodes have the same data at all times, guaranteeing real-time accuracy.

2. Availability (A): Ensures the system responds to all read/write requests, even during failures.

3. Partition Tolerance (P): Allows the system to continue operating despite network partitions that
separate nodes.

In blockchain, a balance between Availability and Partition Tolerance is often chosen. Bitcoin, for
instance, ensures data is accessible even if some nodes are offline, prioritizing availability and partition
tolerance over strict consistency.

7. Draw and explain the working of Blockchain

Working of a Blockchain

1. Transaction Initiation: A user initiates a transaction, such as transferring cryptocurrency to another user.
This transaction is digitally signed with the user’s private key, creating a secure transaction record that
can be verified by others.

2. Broadcasting the Transaction: The transaction is broadcasted to the network, where it is picked up by
nodes (computers) that validate its authenticity.
 3. Transaction Validation: Special nodes, called miners (in PoW networks) or validators (in PoS networks),
validate the transaction to ensure it adheres to network rules. Validation includes checking the sender’s
balance, verifying the digital signature, and confirming the transaction details.

4. Adding the Transaction to a Block: Once validated, the transaction is bundled with others in a new
block. The block contains:

o A unique hash created based on its contents.

o The previous block’s hash, which links it to the previous block.

5. Consensus for Block Addition: The network’s consensus mechanism is activated. For example, in PoW,
miners compete to solve a complex cryptographic puzzle. The first miner to solve it adds the block to the
blockchain and broadcasts it to the network. In PoS, validators are chosen to propose and verify blocks
based on their stake in the network.

6. Block Verification and Addition: Once the block is verified, it is added to the blockchain, with the block’s
hash serving as a unique identifier. The blockchain network’s nodes then update their copies of the
blockchain.

7. Transaction Finalization: With the block added, the transaction is considered confirmed. Each block that
follows the transaction’s block further reinforces its legitimacy, making it increasingly immutable.

8. High Level Diagram of BC architecture

VM: Virtual machine allows Turing complete code to be run on a block chain (as smart contracts); whereas a
transaction script is limited in its operation., State Machine: A blockchain can be viewed as a state transition
mechanism whereby a state is modified from its initial form to the next one and eventually to a final form by
nodes on the blockchain network as a result of a transaction execution, validation, and finalization process

9. Benefits and Limitations of BT

Benefits:

1. Decentralization: Reduces reliance on third parties, empowering peer-to-peer transactions.

 2. Transparency and Trust: Transactions are openly visible, enhancing accountability.

3. Immutability: Ensures data cannot be altered once recorded.

4. Cost Efficiency: Reduces transaction costs by eliminating intermediaries.

5. Enhanced Security: Uses cryptographic protocols, protecting against tampering and unauthorized access.

Limitations:

1. Scalability: Blockchains, especially public ones like Bitcoin, struggle with high transaction volumes.

2. Energy Consumption: PoW consensus demands significant energy, impacting sustainability.

3. Privacy Concerns: While transparent, blockchain does not ensure individual transaction privacy.

4. Integration Challenges: Legacy systems are complex to integrate with blockchain.

5. Regulatory Uncertainty: Lack of clear regulations hinders widespread adoption.

10. What is the task of miners in a blockchain network?

Miners validate and record transactions in a blockchain network. In Proof of Work (PoW) systems,
miners compete to solve complex mathematical puzzles to find a valid hash, thus securing the network
and earning rewards. Their roles include:

1. Verification: Checking transaction validity by confirming that users have the necessary funds and
preventing double-spending.

2. Block Creation: Compiling transactions into a block and securing it through cryptographic hashing.

3. Consensus Contribution: Ensuring that all nodes agree on the chain's state, thus maintaining network
integrity.

Miners also play a role in network security by preventing attacks and promoting network health through
their participation.

11. Methods of Decentralization

1. Disintermediation

Disintermediation removes intermediaries or third-party entities from processes, allowing participants to

interact directly on the blockchain. In a decentralized system, trust in centralized parties like banks or
clearinghouses is replaced by trust in the blockchain protocol.

How it Works:

 Direct Interaction: Users interact directly with each other. For example, in a financial transaction,
instead of using a bank, two users can transact directly on the blockchain using their public
addresses.

 Reduced Costs and Increased Speed: By eliminating intermediaries, transactions can be faster and
more cost-effective.

 Applicability Across Industries: While common in finance, disintermediation also applies to supply
chain management, healthcare, and voting systems, where blockchain ensures data integrity without
third-party validation.

Example:
  Cryptocurrency Transfers: In Bitcoin or Ethereum networks, users transfer funds directly without
banks or payment processors. The transaction is validated by the network rather than a single
authority.

2. Competition-Based Decentralization (Contest-Driven Decentralization)

In competition-based decentralization, multiple service providers or validators compete to offer services

or validate transactions within the system. This method is common in consensus mechanisms like Proof
of Work (PoW), where miners compete to add the next block, and Proof of Stake (PoS), where nodes
with more stake are selected as validators.

How it Works:

 Competitive Model: Validators or miners compete for the chance to validate transactions and earn
rewards. This competition maintains the integrity of the system and ensures that participants act
honestly.

 Enhanced Security: With multiple validators, the network becomes more secure against attacks
since no single entity can control the entire network.

 Varied Decentralization Levels: Depending on the type of consensus and the level of control,
networks can vary from semi-centralized to fully decentralized.

Example:

 Bitcoin’s PoW: Miners compete to solve cryptographic puzzles to earn the right to add a block to the
blockchain. The competitive nature makes it difficult for any single miner to control the network.

12. Consensus Mechanism: PoW, PoET, PoS, DPoS, PoI, PoD, Traditional BFT, Federated BFT, Paxos, RAFT

1. Proof of Work (PoW)

Proof of Work is the original consensus mechanism, first implemented in Bitcoin. In PoW, miners (nodes)
compete to solve complex mathematical puzzles to validate transactions and add them to the
blockchain. This process requires substantial computational power, making it resource-intensive.

 How it Works: Miners solve a cryptographic puzzle to find a valid hash for the block. The first miner to
solve the puzzle broadcasts the block to the network, and other nodes verify its validity.

 Security: It is secure because altering a block would require re-mining all subsequent blocks, which is
practically impossible without controlling over 50% of the network’s computational power (known as a
51% attack).

 Drawbacks: PoW is energy-intensive and can lead to centralization, as only those with substantial
computational power can mine efficiently.

Examples: Bitcoin, Litecoin.

2. Proof of Stake (PoS)

Proof of Stake aims to solve PoW’s energy inefficiency by selecting validators based on the amount of
cryptocurrency they hold and are willing to “stake” as collateral. Validators are chosen at random to
propose and validate new blocks.

 How it Works: Nodes with more significant stakes have a higher chance of being chosen as validators.
Validators are incentivized to act honestly, as malicious actions can result in losing their staked funds.
 Security: PoS is less susceptible to 51% attacks than PoW since attackers would need to control the
majority of the staked tokens, which can be economically prohibitive.

 Drawbacks: Large stakeholders may have an advantage in PoS, leading to some degree of centralization.

Examples: Ethereum 2.0, Cardano, Tezos.

3. Delegated Proof of Stake (DPoS)

Delegated Proof of Stake is a variation of PoS where token holders vote for a select group of nodes
(delegates) who validate blocks on their behalf. DPoS provides faster transaction speeds and higher
scalability.

 How it Works: Token holders delegate their voting power to specific validators. The validators are
responsible for creating new blocks and validating transactions. Misbehaving validators can be voted out
by token holders.

 Security: DPoS relies on community governance, allowing token holders to select trustworthy validators,
but it also depends on maintaining an active voting base.

 Drawbacks: DPoS may result in a more centralized network since only a few delegates control the
network's integrity.

Examples: EOS, Tron, BitShares.

4. Proof of Elapsed Time (PoET)

Proof of Elapsed Time is a consensus mechanism developed by Intel, commonly used in permissioned
blockchains. PoET uses a secure hardware component called the Trusted Execution Environment (TEE) to
ensure random, fair leader selection.

 How it Works: Each validator node requests a random wait time from the TEE. The node with the
shortest wait time is selected to create the next block. PoET ensures fairness by assigning wait times
randomly to all nodes.

 Security: PoET is secure as it leverages hardware-enforced randomization, which is resistant to

tampering. However, it requires specific hardware (Intel SGX) to operate.

 Drawbacks: It has limited applicability in public blockchains due to its dependency on hardware.

Examples: Hyperledger Sawtooth.

5. Proof of Importance (PoI)

Proof of Importance, introduced by the NEM blockchain, goes beyond stake-based selection by also
considering a user’s activity and transaction history. It rewards users who contribute to network growth
and activity, rather than simply holding tokens.

 How it Works: Nodes are scored based on their coin balance, frequency of transactions, and overall
contribution to the network. This “importance score” determines their chances of validating the next
block.

 Security: PoI enhances security by encouraging active participation, which promotes decentralization.

 Drawbacks: It may still favor users with larger balances, as their transaction volume can increase their
importance score.

Examples: NEM.
 6. Proof of Deposit (PoD)

Proof of Deposit requires validators to lock in a specific deposit before they can propose blocks. If they
act maliciously, their deposit is forfeited. PoD is useful for systems requiring permissioned access and
guarantees that validators have a financial incentive to behave honestly.

 How it Works: Validators must deposit a certain amount of cryptocurrency to participate. If they validate
blocks incorrectly or act dishonestly, their deposit is confiscated.

 Security: By financially incentivizing honesty, PoD ensures validators have "skin in the game."

 Drawbacks: If deposit amounts are too high, it can limit validator participation, potentially centralizing
control among those with significant resources.

Examples: Tendermint.

7. Traditional Byzantine Fault Tolerance (BFT)

Traditional Byzantine Fault Tolerance is a consensus mechanism designed for networks where nodes may
act maliciously or fail without warning. BFT ensures that honest nodes can reach a consensus despite the
presence of faulty or malicious nodes.

 How it Works: Nodes communicate by exchanging messages until they reach an agreement on a specific
transaction or state. The process tolerates up to one-third of nodes behaving maliciously.

 Security: BFT is resilient to attacks and node failures, making it suitable for private or consortium
blockchains.

 Drawbacks: BFT does not scale well in large networks due to communication overhead.

Examples: Hyperledger Fabric, Ripple.

8. Federated Byzantine Fault Tolerance (Federated BFT)

Federated BFT, as seen in the Stellar Consensus Protocol, is a modified BFT model where nodes only trust
specific nodes (or federations) rather than the entire network. This trust-based model is useful in
permissioned networks where participants are pre-selected.

 How it Works: Nodes create quorums by selecting trusted nodes, forming a consensus based on a
majority vote within these trusted groups.

 Security: Federated BFT provides efficient consensus in trusted networks but relies on an initial trust
assumption between nodes.

 Drawbacks: This approach may introduce centralization since not all nodes are trusted equally, which
may reduce network resilience.

Examples: Stellar.

9. Paxos

Paxos is a consensus algorithm widely used in distributed computing to achieve agreement on a single
value among multiple nodes in a network. It is resilient to faults and network partitions, making it ideal
for maintaining consistent state in databases and distributed systems.
  How it Works: Nodes in Paxos are divided into proposers, acceptors, and learners. Proposers suggest a
value, which is accepted if a majority of acceptors agree. Once a value is chosen, learners update their
state to reflect the agreed-upon value.

 Security: Paxos is fault-tolerant, enabling consensus even in the presence of faulty nodes, making it ideal
for distributed databases.

 Drawbacks: Paxos is complex and can be slow, limiting its scalability in large networks.

Examples: Used in Google’s Chubby lock service and Apache Cassandra.

10. RAFT

RAFT is a consensus algorithm focused on simplicity and ease of implementation, often used as an
alternative to Paxos in distributed systems. RAFT follows a leader-based approach where one node (the
leader) coordinates consensus.

 How it Works: Nodes are either followers, candidates, or leaders. During each term, a leader is elected
to coordinate log replication, where entries are written to the ledger. Followers respond to the leader,
ensuring consistent data replication across nodes.

 Security: RAFT provides fault tolerance, maintaining consistency even in case of node failures. The leader
election process also minimizes potential conflicts.

 Drawbacks: RAFT is less suited for public blockchains since it depends on a leader-based model, which
may introduce a degree of centralization.

Examples: RAFT is used in distributed databases like etcd and Consul.

Module 2

13. Cryptographic hash functions

14. Hash pointers and Data structures

15. SHA 256

16. Digital Signatures (Or) Explain how do blockchains use private and public-key cryptography?

17. Merkel Tree / Merkel Root

18. PoMembership, PoNonM

19. ECDSA

20. Goofy Coin & Scrooge Coin