SY0-701 Question 48
Single answerBlockchain: Open public ledgerA security architect is evaluating whether to store software supply-chain attestations on a blockchain so customers can independently verify that released binaries have not been altered after publication. The company wants any customer to be able to validate the record history without relying on the company's internal database. Which blockchain characteristic most directly supports this requirement?
- A
An open public ledger that allows anyone to review the transaction history and verify entries independently
- B
A centralized administrator account that can directly edit past blocks if a publishing error is discovered
- C
Built-in encryption of all data on the chain so only the software vendor can read the attestation records
- D
Automatic removal of older blocks after a retention period to reduce the chance of data tampering
Show answer and explanation
Correct answer: A
Explanation
The best answer is the open public ledger because the requirement is not just to store data, but to let external parties independently verify record history. In Security+ terms, blockchain is commonly associated with a distributed, append-only ledger in which participants can validate entries and detect tampering. For software supply-chain attestation, storing hashes or signed proofs on a blockchain can provide transparency and integrity evidence without forcing customers to trust only the publisher's private database. This aligns with general blockchain design principles documented by sources such as NIST, which describe blockchain as a distributed ledger technology intended to provide a shared, tamper-evident record. The other options reflect common misconceptions: blockchain is not meant to rely on a single administrator editing history, it does not inherently make all content private to one party, and its security value depends on preserving historical records rather than deleting them.
- A. Correct.
Correct. An open public ledger is the key blockchain property that supports broad, independent verification. In this scenario, customers need to confirm that attestations were published and have not been altered afterward without trusting only the company's internal systems. Public visibility of the ledger, combined with the chained structure of blocks and consensus validation, enables third parties to inspect the history and detect unauthorized modification attempts.
- B. Incorrect.
Incorrect. This describes a centralized system, not a core blockchain security property. A blockchain is specifically useful here because historical records are intended to be tamper-evident and resistant to unilateral change. Allowing one administrator to edit prior blocks would undermine integrity and nonrepudiation goals.
- C. Incorrect.
Incorrect. Public blockchains are not defined by making all data readable only by the vendor. In fact, the scenario requires customers to verify records independently. While cryptographic techniques such as hashing and digital signatures are relevant, the idea that only the vendor can read the records conflicts with the need for public validation.
- D. Incorrect.
Incorrect. Removing older blocks would weaken the historical audit trail rather than strengthen it. Blockchain value in this use case comes from preserving an append-only record of prior entries. Data retention limits may exist in other systems, but automatic deletion is not the characteristic that supports independent integrity verification.