CompTIA Security+ Question C-96

Which of the following is used to verify data integrity?


Answer: A

SHA stands for “secure hash algorithm”. SHA-1 is the most widely used of the existing SHA hash functions, and is employed in several widely used applications and protocols including TLS and SSL, PGP, SSH, S/MIME, and IPsec. It is used to ensure data integrity.

Note: A hash value (or simply hash), also called a message digest, is a number generated from a string of text. The hash is substantially smaller than the text itself, and is generated by a formula in such a way that it is extremely unlikely that some other text will produce the same hash value.

Hashes play a role in security systems where they’re used to ensure that transmitted messages have not been tampered with. The sender generates a hash of the message, encrypts it, and sends it with the message itself. The recipient then decrypts both the message and the hash, produces another hash from the received message, and compares the two hashes. If they’re the same, there is a very high probability that the message was transmitted intact. This is how hashing is used to ensure data integrity.