NESTOR Session 91 Exam 1 Practice

Salts are random data added to the input of a hash function to defend against rainbow table attacks. When you store a password, you generate a unique salt and compute the hash of the password combined with that salt (hash(password + salt)). The salt is stored with the hash so you can verify future logins by recomputing the hash with the same salt. Because the salt is unique per password, identical passwords produce different hashes, which prevents attackers from using precomputed tables to reverse hashes. This forces attackers to attack each password individually, making guessing far less efficient. The other options miss the purpose: a salt isn’t used to encrypt data with a secret key, it doesn’t increase encryption key length, and it isn’t about ensuring timestamp uniqueness in logs.