What technique is often employed to verify data integrity?

Calculating a checksum is an essential technique used to verify data integrity. A checksum is a value derived from the content of a data set through a mathematical operation, typically involving hashing algorithms. When data is transmitted or stored, a checksum is computed and usually sent or stored alongside the data. Upon retrieval or after transmission, the checksum is recalculated.

If the newly calculated checksum matches the original, it indicates that the data has remained unchanged and intact. On the other hand, if there is a discrepancy, it suggests potential data corruption, tampering, or transmission errors. This method is widely used in various applications, such as file transfers, data storage, and network protocols, to ensure that the data remains pure and unaltered over time.

The other techniques mentioned do not focus on verifying data integrity in the same direct manner. Data compression reduces the size of data without being inherently designed to check for changes in the data itself. File fragmentation divides files into smaller pieces for storage efficiency, and while it can relate to data management, it doesn't verify integrity. Data duplication aims to create copies of data for backup and redundancy purposes, but it does not inherently ensure that the original and duplicate copies are identical unless paired with an integrity check method like checksums.