Which statement best describes the purpose of a checksum?

• A. To encrypt data
• B. To detect errors in data
• C. To verify user credentials
• D. To compress data

Answer: (B)

A checksum is a value derived from the data to help verify its integrity. The idea is to detect changes that may occur during storage or transmission. The sender computes this small value from the data and sends it along with the data; the receiver recomputes the checksum from what was received and compares it to the transmitted one. If they match, the data is likely unchanged; if they don’t, something altered the data en route, indicating an error.

This isn’t about turning data into unreadable form (encryption), verifying who is accessing it (credentials), or shrinking its size (compression). It’s specifically about catching accidental corruption to ensure the data you received is the same as the data that was sent.