Blockchain Security Professional (CBSP) Interview Questions

Passing the Certified Blockchain Security Professional (CBSP) certification exam will validate your proficiency in current security pros and will give you the opportunity to demonstrate your expertise in an emerging space, as well as form a community of elite business executives and cyber specialists. To pass the interview phase you will have to showcase your expertise as a cybersecurity professional with in-depth knowledge of the emerging field of Blockchain security.

You may also go through our Certified Blockchain Security Professional (CBSP) Online tutorial to further strengthen your knowledge base. Our CBSP Free Practice Tests will further help attain your desired certification and become competent to your employers in an ever-changing job market. In order to succeed in your interview, there are certain topics you should be familiar with you before the interview. And for your assistance, we have compiled below, a list of some highly expected CBSP Interview Questions. So let’s begin!

Advanced Interview Questions

What is the most important aspect of blockchain security?

The most important aspect of blockchain security is the protection of the integrity and immutability of the data stored on the blockchain. This is achieved through the use of cryptographic techniques such as hashing, digital signatures, and consensus algorithms that ensure that once data is added to the blockchain, it cannot be altered or deleted. Additionally, blockchain security also involves protecting the confidentiality of data by encrypting sensitive information and ensuring that only authorized parties have access to it.

Other important aspects of blockchain security include:

Protecting the private keys and other sensitive information used to access and manage the blockchain network and its associated assets
Ensuring the availability and accessibility of the blockchain network and its data
Implementing robust governance and compliance mechanisms
Protecting against attacks such as Sybil attacks, 51% attacks and double-spend attacks
Ensuring scalability and data privacy in case of permissioned or permissionless blockchains.

Overall, blockchain security is a multi-faceted and dynamic field that requires continuous monitoring and improvement to protect the network from evolving threats and vulnerabilities.

How do you ensure the confidentiality, integrity, and availability of data in a blockchain network?

Ensuring the confidentiality, integrity, and availability of data in a blockchain network is achieved through a combination of different security measures:

Confidentiality: To ensure the confidentiality of data in a blockchain network, sensitive information can be encrypted before it is added to the blockchain. This makes it unreadable to unauthorized parties. Additionally, access to the blockchain network can be restricted to authorized parties only, such as through the use of private keys or other forms of authentication.
Integrity: To ensure the integrity of data in a blockchain network, cryptographic techniques such as hashing and digital signatures are used to secure the data. Each block in the blockchain contains a hash of the previous block, creating a chain of blocks that can be used to verify the integrity of the data. Additionally, consensus mechanisms such as Proof of Work (PoW) or Proof of Stake (PoS) can be used to ensure that the data on the blockchain is consistent across all nodes in the network.
Availability: To ensure the availability of data in a blockchain network, measures such as distributed storage and replication can be used to ensure that multiple copies of the blockchain exist across different nodes in the network. This makes it less likely that the blockchain will become unavailable due to the failure of a single node. Additionally, measures such as load balancing and failover can be used to ensure that the blockchain remains accessible and responsive even under high traffic conditions.
Governance: To ensure that the data on the blockchain network is only accessible by authorized parties, it is important to have robust governance and compliance mechanisms in place. This can include, implementing access controls and permission management, monitoring network activity and user behavior, and performing regular security assessments.

Overall, ensuring the confidentiality, integrity, and availability of data in a blockchain network requires a comprehensive and multi-layered approach that includes a combination of cryptographic techniques, access controls, and governance mechanisms.

Can you describe a scenario where a smart contract has been exploited and explain how it could have been prevented?

A smart contract is a self-executing contract with the terms of the agreement between buyer and seller being directly written into lines of code. Due to the nature of smart contracts, an exploit of a smart contract can cause significant financial losses and reputational damage.

One example of a smart contract exploit is the “The DAO” hack in 2016, which resulted in the theft of 3.6 million Ether (worth around $50 million at the time) from the Decentralized Autonomous Organization (DAO). The hack exploited a vulnerability in the smart contract that allowed the attacker to repeatedly withdraw the same funds multiple times before the smart contract could update the balance. This exploit was made possible by the lack of a “recursive call” mechanism in the smart contract, which is a mechanism that prevents re-entrancy.

The hack could have been prevented by implementing a “recursive call” mechanism to prevent re-entrancy or by conducting a thorough security audit of the smart contract code before deployment. Additionally, having a robust governance and compliance mechanism in place, such as incident response plan, would also have helped to minimize the impact of the hack.

Another example is the “Parity Wallet” hack, which resulted in the loss of $31 million worth of Ether. This hack was made possible by a vulnerability in the smart contract code that allowed the attacker to gain control of the smart contract and steal the funds stored in it.

This hack could have been prevented by conducting a thorough security audit of the smart contract code before deployment, and by implementing appropriate access controls and permission management.

In both examples, the vulnerability was present in the smart contract code, and could have been identified and prevented through proper code review and testing before deployment. It is important to note that smart contract security is a complex field and requires a multi-disciplinary approach and expertise in areas such as cryptography, computer science and code review.

How do you secure a private blockchain network?

Securing a private blockchain network involves implementing a combination of different security measures to protect the confidentiality, integrity, and availability of the data stored on the blockchain. Some of the key ways to secure a private blockchain network include:

Network security: This includes securing the communication channels between the different nodes in the network, such as through the use of secure protocols like HTTPS and SSL/TLS. It also includes securing the physical infrastructure of the network, such as by protecting the servers and other hardware that the blockchain runs on.
Access control: This includes implementing mechanisms to ensure that only authorized parties can access the blockchain network and the data stored on it. This can include the use of private keys, digital certificates, and other forms of authentication to control access.
Data encryption: To ensure the confidentiality of data stored on the blockchain, it can be encrypted before it is added to the blockchain. This makes it unreadable to unauthorized parties, even if they are able to access the blockchain.
Consensus mechanism: A consensus mechanism such as Proof of Work (PoW) or Proof of Stake (PoS) can be used to ensure that the data on the blockchain is consistent across all nodes in the network.
Smart contract security: Smart contracts are self-executing contracts, it’s important to ensure that the smart contracts on the blockchain network are secure. This can be done by conducting a thorough security audit of the smart contract code before deployment, and by implementing appropriate access controls and permission management.
Monitoring and incident response: Having a robust incident response plan and monitoring the network for unusual activity can help detect and respond to potential security breaches in a timely manner.
Compliance and Governance: Private blockchain often needs to meet industry and regulatory standards, it’s important to have robust governance and compliance mechanisms in place. This can include, implementing access controls and permission management, monitoring network activity and user behavior, and performing regular security assessments.

It’s important to note that blockchain security is a complex field and requires a multi-disciplinary approach and expertise in areas such as cryptography, computer science, and network security.

How do you secure communication between nodes in a blockchain network?

Securing communication between nodes in a blockchain network is crucial to ensure the confidentiality, integrity, and availability of data on the blockchain. Some key ways to secure communication between nodes include:

Secure protocols: Communication between nodes can be secured through the use of secure protocols like HTTPS and SSL/TLS. These protocols use encryption to protect the data being transmitted, making it unreadable to unauthorized parties.
Public-private key encryption: Each node in the blockchain network can have a unique public-private key pair. Data can be encrypted with a node’s public key, and only the node with the corresponding private key can decrypt it. This ensures that only authorized parties can read the data.
Digital certificates: Each node in the network can have a digital certificate that verifies its identity. This can be used to authenticate nodes and ensure that only authorized parties can access the blockchain network.
Firewall and intrusion detection: Firewalls can be used to restrict access to the blockchain network and protect it from external attacks. Intrusion detection systems can be used to detect and respond to any suspicious activity on the network.
Virtual Private Network (VPN): A VPN can be used to create a secure, encrypted tunnel between nodes in the network. This ensures that data transmitted between nodes is protected from eavesdropping and tampering.
Multi-factor authentication (MFA): To secure communication between nodes, multi-factor authentication can be implemented, requiring multiple forms of identification such as password, fingerprint or biometrics before allowing access.

It’s important to note that securing communication between nodes in a blockchain network is a complex task and requires a multi-disciplinary approach and expertise in areas such as cryptography, computer science and network security. It’s also important to keep the network and all its components updated with the latest security patches and to regularly review and assess the security of the network.

How do you handle and prevent Sybil attacks in a blockchain network?

A Sybil attack is a type of attack on a decentralized network where an attacker creates multiple identities (i.e., “Sybils”) in order to gain control of a significant portion of the network. In a blockchain network, this can be used to control a significant portion of the network’s computational power, manipulate consensus, and disrupt the integrity of the network.

Some ways to handle and prevent Sybil attacks in a blockchain network include:

Proof of Work (PoW) or Proof of Stake (PoS): These consensus mechanisms can be used to make it more difficult for an attacker to create multiple identities and control a significant portion of the network. PoW requires nodes to perform a significant amount of computational work in order to participate in the network, while PoS requires nodes to hold a significant amount of cryptocurrency in order to participate in the network.
Identity verification: This can include requiring nodes to submit proof of identity, such as a government-issued ID, before being allowed to participate in the network. This makes it more difficult for an attacker to create multiple identities.
Whitelisted nodes: A network can be configured to only allow a specific set of nodes to participate in the network. This makes it more difficult for an attacker to create multiple identities and join the network.
Reputation-based systems: Reputation-based systems can be used to assign a reputation score to each node on the network. Nodes with a higher reputation score can be granted more privileges, while nodes with a lower reputation score may be restricted or removed from the network.
Detection and response: Regularly monitoring network activity can help detect and respond to Sybil attacks in a timely manner. This includes identifying and isolating malicious nodes, and taking appropriate action such as banning them from the network.
Decentralized Identity (DID): Decentralized Identity (DID) is a new way to establish trust and provide privacy-preserving identity management in a blockchain network. DID can be used as a decentralized and self-sovereign identity solution, providing a secure and private way to create and manage identities on the network.

It’s important to note that preventing Sybil attacks in a blockchain network requires a multi-disciplinary approach, including a combination of technical and non-technical solutions and expertise in areas such as cryptography, computer science and network security.

How do you ensure the authenticity and non-repudiation of transactions in a blockchain network?

Ensuring the authenticity and non-repudiation of transactions in a blockchain network is essential to maintaining the integrity of the network and preventing fraud. Some ways to achieve this include:

Cryptographic signatures: Each transaction in a blockchain network is digitally signed by the sender using a private key. The signature is verified using the sender’s public key, which is stored on the blockchain. This ensures that only the rightful owner of the private key can authorize a transaction, and that the transaction cannot be modified after it has been signed.
Hash functions: Each transaction in a blockchain network is also hashed using a cryptographic hash function. The hash is stored along with the transaction in the blockchain. Hash functions are one-way, meaning that it is computationally infeasible to determine the original transaction from the hash. This ensures that the integrity of the transaction cannot be compromised.
Time-stamping: Transactions in a blockchain network are time-stamped, which can help establish when the transaction occurred, and in what order. This can be useful in case of disputes and allows to track the chronological order of the transactions.
Consensus mechanism: The consensus mechanism used in a blockchain network ensures that all nodes on the network agree on the validity of a transaction before it is added to the blockchain. This ensures that only valid transactions are added to the blockchain, and that invalid transactions are rejected.
Smart Contracts: Smart contracts are self-executing contracts with the terms of the agreement between buyer and seller written into lines of code. The smart contract can automatically validate and execute the transactions, thus providing an additional layer of authenticity and non-repudiation.
Multi-Signature: Multi-signature (or multisig) is a digital signature scheme which allows a group of users to sign a single document. In a blockchain network, multi-signature can be used to ensure that multiple parties must sign off on a transaction before it is executed, providing an additional layer of security and non-repudiation.

It’s important to note that, no single technique can provide complete security, multiple layers of security are necessary to ensure the authenticity and non-repudiation of transactions in a blockchain network.

How do you handle forks and chain re-organization in a blockchain network?

Handling forks and chain re-organizations in a blockchain network can be a complex process that requires careful consideration and planning. Some of the key considerations and strategies for handling these issues include:

Consensus mechanism: The consensus mechanism used in a blockchain network can play a critical role in how forks and chain re-organizations are handled. For example, in a proof-of-work (PoW) blockchain, forks are resolved by the longest chain rule, where the longest chain is considered the valid chain. In a proof-of-stake (PoS) blockchain, forks may be resolved by a voting process among the validators.
Monitoring: Monitoring the blockchain network for potential forks and re-organizations can help quickly identify and address any issues that arise. This may include monitoring for conflicting transactions, or for changes in the block hash or chain length.
Communication: Communicating with other nodes on the network can help resolve issues related to forks and re-organizations. This may include discussing potential issues, agreeing on a resolution, and sharing information about the current state of the blockchain.
Backup and recovery: Having a backup and recovery plan in place can help minimize the impact of forks and re-organizations on the blockchain network. This may include regularly backing up the blockchain, or having a mechanism in place for quickly rolling back to a previous version of the blockchain.
Soft forks and hard forks: A soft fork is a change to the protocol that is backwards-compatible with older versions of the software. A hard fork is a change to the protocol that is not backwards-compatible. Soft forks are less disruptive and often can be adopted gradually. Hard forks may require all the nodes to update their software and can be more disruptive.
Replay protection: Replay protection is a mechanism that prevents transactions from being replayed across different chains. This can help prevent issues with double-spending and other malicious activities.

It’s important to note that, forks and re-organizations can be a natural occurrence in a blockchain network and not always malicious. It’s important for the network participants to have a plan and protocol to handle them in a way that preserves the integrity and continuity of the network.

How do you secure the storage of private keys used in a blockchain network?

Securing the storage of private keys used in a blockchain network is crucial for ensuring the confidentiality and integrity of transactions on the network. Some of the key strategies for securing private keys include:

Hardware security modules (HSMs): HSMs are specialized devices that are designed to securely store and manage private keys. They use physical and logical security measures to protect the keys from unauthorized access.
Cold storage: Cold storage refers to the practice of storing private keys offline, such as on a USB drive or a paper wallet. This can help protect the keys from hacking or other online threats.
Multi-sig: Multi-sig or multi-signature, is a security feature that requires multiple parties to sign a transaction before it can be executed. This can help prevent unauthorized access to private keys.
Key management systems: Key management systems (KMS) are software systems that are designed to securely manage and store private keys. They may provide features such as key rotation, key archival, and key recovery.
Encryption: Encrypting private keys with a strong algorithm, such as AES-256, can help protect the keys from unauthorized access even if they are stolen or lost.
Regularly backup: Regularly backing up private keys can help ensure that they can be recovered in the event of a disaster or other emergency.
Physical security: Physical security measures, such as security cameras, biometric scanners, and security personnel, can help protect private keys from theft or unauthorized access.

It’s important to note that, private keys are the most sensitive asset in a blockchain network and can compromise the entire network if compromised. It’s important to have a good key management system in place and regularly review and update it as the security landscape evolves.

Can you explain the difference between a 51% attack and a double-spend attack and how they can be prevented in a blockchain network?

A 51% attack and a double-spend attack are both types of malicious attacks that can be used to disrupt the operation of a blockchain network.

A 51% attack occurs when a malicious miner or group of miners controls more than 50% of the computational power (hashrate) of a blockchain network. This allows them to control the creation of new blocks and can potentially be used to reverse or modify previous transactions. To prevent a 51% attack, a blockchain network can use a consensus algorithm that is resistant to such attacks, such as Proof of Work (PoW) or Proof of Stake (PoS)

A double-spend attack occurs when a malicious actor attempts to spend the same cryptocurrency multiple times by sending the same transaction to multiple nodes on the network. This can be prevented by using a consensus algorithm that ensures that only one version of a transaction is considered valid by the network, such as Confirmations in PoW or PoS or by using a central authority like a bank.

Another way of preventing 51% attack is by implementing a decentralized network where the control of the network is distributed among different stakeholders, making it difficult for a single entity to control more than 50% of the network.

In addition to these, other prevention methods include monitoring for unusual patterns of activity on the network, implementing fraud detection systems, and educating users about the risks of malicious attacks.

How do you ensure regulatory compliance in a blockchain network?

Ensuring regulatory compliance in a blockchain network can be a complex process, as regulations vary depending on the jurisdiction and the specific use case of the blockchain. However, some general strategies that can be used to ensure regulatory compliance include:

Know Your Customer (KYC) and Anti-Money Laundering (AML) procedures: Implementing KYC and AML procedures can help ensure that transactions on the blockchain network comply with laws and regulations related to financial crime prevention.
Data privacy and protection: Ensuring that personal data is protected and that transactions are conducted in compliance with data protection regulations, such as the General Data Protection Regulation (GDPR) or the California Consumer Privacy Act (CCPA)
Smart contract auditing: Auditing smart contracts to ensure that they are free from vulnerabilities and operate in compliance with laws and regulations.
Compliance monitoring: Regularly monitoring the blockchain network for compliance with laws and regulations, such as suspicious transactions, compliance with international sanctions, and other compliance-related issues.
Collaboration with Regulators: Collaborating with regulators and industry bodies can help ensure that the blockchain network is developed and operated in compliance with laws and regulations.
Compliance reporting: Generating reports that demonstrate compliance with laws and regulations, such as suspicious activity reports (SARs) or know-your-customer (KYC) reports.

It’s important to note that regulatory compliance is an ongoing process and laws and regulations are changing all the time, therefore, it’s important to regularly review and update compliance processes as necessary.

How do you implement multi-signature transactions in a blockchain network?

Multi-signature (also known as multi-sig) transactions in a blockchain network allow multiple parties to control access to the funds by requiring multiple signatures before a transaction can be executed. Here are the general steps for implementing multi-signature transactions in a blockchain network:

Create a multi-signature address: A multi-signature address is a unique address that is associated with multiple public keys. It can be generated using a specific smart contract or a specific application or library.
Associate public keys with the multi-signature address: Public keys of the parties who are authorized to sign the transactions are associated with the multi-signature address.
Set the threshold number: The threshold number is the minimum number of signatures required to authorize a transaction. For example, if the threshold is set to 2, at least 2 of the associated public keys must sign the transaction for it to be authorized.
Sign the transactions: Each authorized party signs the transaction using their private key.
Broadcast the transaction: Once the transaction has the required number of signatures, it is broadcasted to the blockchain network for validation and execution.

The implementation details may vary depending on the blockchain platform being used, but the general process is similar across most blockchain networks. Multi-sig transactions can increase the security of the network as it eliminates the risk of a single point of failure, and it can be used for various use cases like corporate governance, voting, and fund management.

How do you handle scalability issues in a blockchain network?

Scalability is one of the major challenges facing blockchain networks, as the number of transactions that can be processed per second is limited. Here are some common strategies for handling scalability issues in a blockchain network:

Sharding: Sharding is a technique where the blockchain is divided into smaller, more manageable pieces called “shards.” Each shard can process transactions independently, allowing for a more efficient use of resources and an increase in the number of transactions that can be processed per second.
Off-chain transactions: Some blockchain networks, like the Lightning Network for Bitcoin or the Raiden Network for Ethereum, use off-chain transactions to increase scalability. In off-chain transactions, the actual transfer of funds takes place off the blockchain, with only the final balance being recorded on the blockchain.
State channels: Similar to off-chain transactions, state channels allow multiple transactions to occur between two parties without the need for each transaction to be recorded on the blockchain. This reduces the number of transactions that need to be processed on the blockchain, increasing scalability.
Layer 2 Scaling: Layer 2 Scaling solutions like Plasma and Truebit extend the capability of the blockchain by moving some of the computation off-chain. This way the main chain is not bogged down with all the computation, and it can scale better.
Reducing data storage: Some blockchain networks use techniques like state pruning, which discards old data no longer required by the network, to reduce the amount of data that needs to be stored, allowing for a more efficient use of resources.
Increase block size: By increasing the block size, more transactions can be stored in each block, which can help increase the number of transactions that can be processed per second.

It’s important to note that scalability is a complex and ongoing problem in blockchain technology, and different solutions may be more or less effective depending on the specific use case of the blockchain network.

Can you explain the difference between a permissioned and a permissionless blockchain network?

A permissioned blockchain network, also known as a private blockchain network, is a network where access to the network is restricted to a specific group of participants. These participants are typically identified and vetted by a central authority, and only authorized participants are allowed to access the network. In this type of network, the consensus mechanism is typically a variation of a proof-of-stake algorithm, or a customized consensus algorithm. This type of network is often used for enterprise use cases where only a certain group of participants should have access to the network and its data.

On the other hand, a permissionless blockchain network, also known as a public blockchain network, is a network where anyone can participate without the need for prior authorization. These networks are decentralized and rely on a consensus mechanism such as proof-of-work algorithm, to ensure that the network remains secure and that the integrity of the data is maintained. Public blockchain networks, such as Bitcoin and Ethereum, are open to anyone and are typically used for decentralized applications and digital assets.

In summary, the main difference between a permissioned and a permissionless blockchain network is that permissioned networks are restricted to a specific group of participants, while permissionless networks are open to anyone. As a result, permissioned networks are typically used for enterprise use cases, while permissionless networks are used for decentralized applications and digital assets.

How do you handle the problem of data privacy in a public blockchain network?

Handling data privacy in a public blockchain network can be a challenging task, as the transparency and immutability of the network can make it difficult to protect sensitive information. However, there are several approaches that can be used to address this problem:

Encryption: One way to protect sensitive data in a public blockchain is to encrypt it before it is added to the blockchain. This can be done using a variety of encryption methods, such as symmetric or asymmetric encryption. This ensures that only authorized parties with the appropriate decryption key can access the data.
Zero-knowledge proof: Another way to handle data privacy in a public blockchain network is to use zero-knowledge proof (ZKP) technology. ZKP allows a user to prove that they possess a certain piece of information without revealing the actual information. This can be used to prove the authenticity of a transaction without revealing the details of the transaction.
Privacy-enhancing technologies: There are several privacy-enhancing technologies (PETs) that can be used to protect sensitive information on a public blockchain. Examples include ring signatures, stealth addresses, and confidential transactions. These technologies allow for increased privacy and anonymity in transactions.
Sidechain or off-chain solutions: Another approach is to use sidechain or off-chain solutions to handle sensitive data in a public blockchain network. In this approach, sensitive data is stored off the main blockchain and is only referenced on the main blockchain.
Consortium or hybrid blockchain: Using a consortium or hybrid blockchain where a subset of trusted participants validate transactions and keep private information off the mainchain.

It’s worth noting that these solutions are not mutually exclusive, and a combination of these methods can be used to provide a more comprehensive approach to data privacy in a public blockchain network.

Basic Interview Questions

1. Why are elliptic curves used in cryptography?

The elliptic curve provides security similar to classical systems (such as RSA), but uses far fewer bits
Implementation of elliptic curves in cryptography requires a smaller chip size, less power consumption, an increase in speed, etc.

2. What are the basic security properties of blockchain?

Basic blockchain security is based on principles of cryptography, decentralization, and consensus. These three principles ensure trust in transactions. In most blockchains or distributed ledger technologies (DLT), the data is structured into blocks that contain transactions or bundles of transactions.

3. Does blockchain solve the Byzantine Generals Problem?

The Byzantine Generals Problem is a concept that explains why money has historically been controlled by a central authority. Bitcoin, the first true cryptocurrency, was invented to solve the Byzantine Generals Problem. The Proof-of-Work mechanism and blockchain are used to achieve consensus across the decentralized system of computers that power the Bitcoin network.

4. What are the types of consensus algorithms in blockchain?

Proof of Work (POW)
Proof of Stake (POS)
Practical Byzantine Fault Tolerance (PBFT)

5. What is a zero-knowledge proof in blockchain?

The zero-knowledge proof is a cryptographic technique that makes sure that no information is revealed during a transaction except for the interchange of some value that is known to both the prover and verifiers.

6. What problem does a zero-knowledge proof best solve?

The new technology called a zero-knowledge proof can transmit sensitive information like authentication information with better security. It builds a secure channel that the users can use their data on without revealing it. This way, they could avoid data leakage in the worst scenarios.

7. What is a smart contract security audit?

A smart contract security audit is a detailed review of the code in a project’s smart contracts. These are important to safeguard funds invested through them. As all transactions on the blockchain are final and immutable, funds cannot be retrieved should they be stolen.

8. How do you prove Turing’s completeness?

To prove that a given language is Turing-complete, give a recipe for translating any given Turing machine into an equivalent program in the language in question, or provide a translation scheme from another language, one that has already been proven to be Turing-complete.

9. What is blockchain architecture?

The elements of blockchain technology include the node, or end-user computer; the block, a data structure storing a set of transactions; and the transaction, which is the smallest unit of information processed in a blockchain system.

10. Which is faster public or private blockchain?

Private blockchains can process transactions in real-time, unlike public blockchains where consensus-building can take time. This is because a private blockchain has a more centralized network than a public blockchain, where the decision-making is much faster.

11. Is public blockchain more secure than private blockchain?

Public blockchains are designed to remove the need for intermediaries in any exchange of asset value scenario. They can be slow and resource-intensive, but they are more secure because of the computational power needed to maintain a distributed ledger.

12. What are Permissioned Blockchains?

A permissioned ledger is a distributed database that is not publicly accessible. It can be accessed only by users with permission. These users can only perform certain actions, governed by the administrators of the blockchain project and are required to identify themselves using digital certificates or other means.

13. What are the vulnerabilities of blockchain?

Because blockchains are decentralized and distributed, cybercriminals employ several strategies for attacking blockchains. These include phishing, Sybil, routing, and 51% attacks.

14. What are the different types of nodes in blockchain?

Light Nodes
Archival Full Nodes
Pruned Full Nodes
Mining Nodes
Authority Nodes
Masternodes
Lightning Nodes

15. What are the security implications of Ethereum?

The Ethereum blockchain is the system on which ETH runs; it secures ETH transactions in a similar manner to how the Bitcoin blockchain secures BTC transactions. The Ethereum platform is maintained by all the connected computers in its network — which makes it secure from interference.

16. Is Hyperledger a private blockchain?

Hyperledger Fabric is one of the blockchain projects within Hyperledger, an umbrella enterprise-focused open-source project positioned as a collaborative development effort created to advance blockchain technology. It uses smart contracts and is similar in many ways to other blockchain technologies. Hyperledger Fabric differs from some other systems, however, in that it is private and permissioned.

17. What is the difference between Hyperledger and blockchain?

Blockchain is a technology based on immutable records called blocks. It uses cryptography to secure these blocks in a decentralized manner. Hyperledger is an open-source platform that allows people to develop Blockchain applications privately.

18. Is Corda a blockchain?

Transactions on Corda are cryptographically linked or chained to the transaction they depend on. Unlike traditional blockchains, Corda does not batch up transactions needing confirmation—into a block—and confirm the entire batch in one go.

19. Does business continuity include disaster recovery?

Business continuity is an organization’s plan to keep its critical functions running in the event of a disaster, while disaster recovery pertains to the actions required to get the business up and running again after a disaster.

20. Why is scalability important in blockchain?

Once a technology meets or exceeds a critical mass of users, it becomes cheaper to operate, making the experience more accessible to new users. If an experience is exclusive but has achieved critical mass, it maintains its exclusivity and prevents non-users from participating.

21. What is an eclipse attack in blockchain?

In an eclipse attack, a malicious actor obscures the view of users within a peer-to-peer (P2P) network by disconnecting specific users. The malicious actor may be set up for more complex attacks or cause general disruption.

22. What is a Sybil attack in blockchain?

A Sybil attack is one in which an attacker pretends to be so many people at the same time. It is a common problem when connecting to peer-to-peer networks. The perpetrator of a Sybil attack has control over the whole network and manipulates it at will.

23. Can hacked Bitcoin be recovered?

If hacked funds can’t be recovered, however, blockchain technology still offers the possibility of tracking stolen crypto in the event that it was transferred to another wallet. If that’s the case, though, you can use blockchain technology to identify where those stolen funds went and track down the bad guys.

24. What are the vulnerabilities in smart contracts?

The vast majority of smart contracts deal with financial assets. If a smart contract contains any errors, these will not be able to be corrected because blockchain is an immutable ledger. If any changes are made in the blockchain state caused by fraudulent or faulty transactions, these cannot be rolled back.

25. What is timestamp Dependence?

This vulnerability occurs when a smart contract uses the block timestamp to determine the conditions to perform a transaction (e.g., sending ether) or as a source of entropy to generate random numbers.

26. What is a block timestamp?

The timestamp is a small, automatically generated record stored in each block that serves to define the exact moment in which this block has been mined and validated by the blockchain network. The blockchain comprises sequential data called blocks that are added to the chain one after another. Each block has a timestamp that determines when it was created.

27. Is DAG superior to blockchain?

Directed acyclic graph technology is different than blockchain technology. Whereas blockchain requires proof of work for each transaction, DAG technology gets rid of blocks entirely; transactions are validated by each other, leading to one transaction being dependent on the preceding one.

28. What is the advantage of DAG?

Due to its block-less nature, transactions run directly into a DAG network. This allows for faster transactions. Because there are no miners on such a system, the system needs a different method of verifying transactions.

29. What does the Lightning Network do?

The lightning network is a technological solution that introduces off-ledger transactions to achieve faster transaction speeds on the bitcoin blockchain.

30. What are sidechains blockchain?

An interchain or sidechain is a standalone blockchain network that connects to another blockchain – called a parent or main net- via a two-way dependency graph.