IT Specialist – Software Development Practice Test 2026: The Comprehensive All-in-One Guide for Exam Success!

Hashes are used to detect tampering because they produce a fixed-size digest of the data, and even small changes to the content typically yield a different digest. When you attach a digital signature, you sign that digest with a private key, so the recipient can verify the signature using the public key after recomputing the hash. If the data were altered in transit, the computed hash would not match the signed digest, and the signature verification would fail, revealing tampering. This approach provides both integrity (the data hasn’t changed) and authenticity/non-repudiation (the data came from the claimed source).

The other options don’t fit: decryption is about converting encrypted data back to plaintext and doesn’t inherently detect tampering; a dictionary is unrelated to data integrity in transit; DML is about database commands and also not about detecting tampering.