71. How are blocks changed together?
A hash value assigned to a block is used to chain them together. If the hash value is changed, this means someone is trying to spoof the data stored in the hash. The link between blocks is done by storing the hash value of the previous block. For example, block 3 will store the hash value of block 2 and so on.
72. Can blocks be removed from a blockchain?
The removal of blocks from a blockchain entirely depends on how it is handled. It is not possible to manually remove a block. However, if it is lost, the blockchain generally tries to rebuild the database using other peers. Once they are verified, they can be deleted to lower the blockchain size as it is not required anyone to do normal operations. It can be re-downloaded again when needed. This process is known as pruning.
73. Can the data stored in a block modified once it is written? If so, why?
The data stored on the blockchain is protected with proper encryption using a digital signature. This makes the data written in a block as a one-time process only. It cannot be altered by any means.
Blockchain database is completely decentralized and consists of several nodes. The nodes take part in the consensus when a new data is added. It provides a complete decentralized solution. Blockchain database offers better transparency and integrity. One more difference between these two types of databases is how they read and write data. The traditional database uses CRUD whereas blockchain uses sequential data writing.
Comparison Between Blockchain and DatabaseIf you want to prepare against similar blockchain questions regarding the database, we recommend reading the Blockchain vs. Database article.
74. What is block identifiers?
Every block on a blockchain has a unique identifier. It is the hash value that acts as a unique identifier. This means that no two blocks identifiers will be identical.
75. What are the threats to the information you are familiar with?
There are lots of threats to information in the present scenario. Due to increase in online transactions over the internet, many hackers have become active and are adopting new approaches to hack information and servers that contain financial information.
The major threat is software attack, identity theft, information extortion, as well as sabotage. In addition to this, Trojan horses, worms, and viruses are other trouble creators.
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76. How will you handle the risk management when it comes to securing the transactions records?
It is basically a process of finding the threats and all the vulnerabilities to the financial records of an organization. The best thing that can be done with this approach is to take the right countermeasures against them immediately.
Another approach is to pay attention to a backup plan. Based on the value of information, more approaches such as buying new risk management software can simply be considered. The prime risk to information is from black-hat hackers.
77. What is Consensus algorithm?
Consensus algorithm is the method of gaining consensus on a change of a data over the system or distributed network. Consensus algorithms are heavily used in blockchains as they enable the network of unknown nodes to reach consensus on the data that is being stored or shared through the blockchain. Some of the most popular consensus algorithms include Proof-of-Stake(PoS) and Proof-of-Work(PoW)
78. What do you understand by ICO?
ICO stands for Initial Coin Offering. It is similar in concept with an IPO(Initial Public Offering). ICO is used by startups or companies to raise capital for their product. It can be a direct blockchain product or a product that utilize the benefits of the blockchain. To raise the money they sell their platform or service tokens.
79. Blockchain is a distributed database. How does it differ from traditional databases?
| Properties | Blockchain | Traditional Database |
| Operations | Only Insert Operations | Can perform C.R.U.D. operations |
| Replication | Full Replication of block on every peer | Master Slave Multi-Master |
| Consensus | Majority of peers agree on the outcome of transactions | Distributed Transactions (2 phase commit) |
| Invariants | Anybody can validate transactions across the network | Integrity Constraints |
80. Is ICO understanding required to get a complete picture of blockchain technology?
ICO is one of the important parts of the blockchain ecosystem. This doesn’t mean that you need to learn about ICO and how they are implemented. But, in the current market, having an ICO understanding is always a good thing to have. ICO is one of the best use-cases of blockchain technology.
