CompTIA Security+ Question K-6

An online store wants to protect user credentials and credit card information so that customers can store their credit card information and use their card for multiple separate transactions.
Which of the following database designs provides the BEST security for the online store?

A. Use encryption for the credential fields and hash the credit card field
B. Encrypt the username and hash the password
C. Hash the credential fields and use encryption for the credit card field
D. Hash both the credential fields and the credit card field

Answer: C

Hashing refers to the hash algorithms used in cryptography. It is used to store data, such as hash tables. One main characteristic of hashing is that the algorithm must have few or no collisions – in hashing two different inputs does not give the same output. Thus the credential fields should be hashed because anyone customer will have a unique credit card number/identity and since they will use their credit cards for many different transactions, the credit card field should be encrypted only, not hashed.