Correct Option
The correct option is 1, 2 and 4.
[as per provisional answerkey]Explanation
Blockchain is a distributed ledger technology (DLT) characterized by decentralization, transparency, and immutability. It functions as a shared database where transactions are recorded in blocks, secured by cryptography, and validated through consensus mechanisms across a peer-to-peer network.
- Statement 1 is Correct: Blockchain provides high transparency while maintaining data integrity. Authorized stakeholders can view the records, but the cryptographic hashing ensures that any attempt to alter the data is detectable, effectively eliminating the risk of unauthorized modification.
- Statement 2 is Correct: Unlike centralized databases, blockchain operates on a distributed network. Every participating node maintains a copy of the entire ledger. When a new block is added, the network synchronizes across all nodes almost instantaneously to ensure a single version of truth.
- Statement 3 is Incorrect: While a Consortium blockchain is indeed a "semi-private" system managed by a group of organizations, the statement is technically incomplete or misleading in the context of standard blockchain classification. A blend of public and private blockchains is more accurately defined as a Hybrid Blockchain. In a Consortium blockchain, the consensus process is controlled by a pre-selected set of nodes, rather than being a simple blend of public/private access.
- Statement 4 is Correct: Blockchain utilizes cryptographic hashing and consensus protocols (like Proof of Work or Proof of Stake). Once a transaction is verified and added to a block, changing it would require recalculating the hashes of all subsequent blocks and gaining control of the majority of the network (51% attack), which is computationally and mathematically considered impossible in a sufficiently decentralized network.
Key Takeaway: Blockchain's core utility lies in its immutability (secured by hashing) and decentralization (distributed ledger), which ensures that data once recorded cannot be altered or deleted without network-wide consensus.