Which statement about checksums is true?

Which statement about checksums is true?

• A. It prevents data loss.
• B. It encrypts data.
• C. It compresses data.
• D. It detects errors by verifying data contents using a checksum value.

Answer: (D)

Checksums serve to verify data integrity by generating a small value from the data itself. The sender attaches this checksum; the receiver recalculates the checksum from the received data and compares it to the attached value. If they match, the data is likely intact; if they differ, corruption or tampering occurred. This makes checksums useful for error detection. They do not prevent data loss, nor do they encrypt or compress data—encryption hides content, compression reduces size, while a checksum only flags changes. In higher-level uses, stronger methods like CRCs or cryptographic hashes improve reliability, but the basic idea remains: detect errors by verifying data contents using a checksum value.

Checksums serve to verify data integrity by generating a small value from the data itself. The sender attaches this checksum; the receiver recalculates the checksum from the received data and compares it to the attached value. If they match, the data is likely intact; if they differ, corruption or tampering occurred. This makes checksums useful for error detection. They do not prevent data loss, nor do they encrypt or compress data—encryption hides content, compression reduces size, while a checksum only flags changes. In higher-level uses, stronger methods like CRCs or cryptographic hashes improve reliability, but the basic idea remains: detect errors by verifying data contents using a checksum value.