With reference to "Blockchain Technology", consider the following statements : 1. It is a public ledger that everyone can inspect, but which no single user controls. 2. The structure and design of blockchain is such that all the data in it are about cryptocurrency only. 3. Applications that depend on basic features of blockchain can be developed without anybody's permission. Which of the statements given above is/are correct ?
- (a) 1 only
- (b) 1 and 2 only
- (c) 2 only
- (d) 1 and 3 only ✓ UPSC's answer
Why the answer is (d)
• A blockchain is a distributed ledger replicated across many nodes; in public chains anyone can inspect it and no single user controls it (statement 1).
• Statement 3 is correct: public blockchains such as Ethereum are 'permissionless' — anyone can build decentralised applications and smart contracts on them without approval.
• Statement 2 is wrong: blockchains can record any data — land records, supply-chain events, votes, health records — not just cryptocurrency.
• Private/permissioned blockchains also exist for enterprises.
• Hence 1 and 3 only, option (d).
Why the other options are wrong
- (a) 1 only
- Statement 3 is also correct: public blockchains are permissionless.
- (b) 1 and 2 only
- Statement 2 is wrong: blockchains store many kinds of data.
- (c) 2 only
- Statement 2 is wrong.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2020, held on 4 October 2020. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.