A security engineer needs to implement password authentication on a highly specialized system. A requirement is that if two different users specify the same password, the stored digests will not be the same. How can this be accomplished?
a. Use a different asymmetrical encryption key for each user.
b. Use SHA instead of MD5 as the hashing algorithm to create the digest.
c. Implement salting to make dictionary and brute-force attacks more difficult.
d. Use peppering techniques that slightly modify the password hashing function.