What is the main purpose of salting in hashing?

The primary purpose of salting in hashing is to prevent rainbow table attacks. When a salt is added to a password before it is hashed, it introduces a unique value that is combined with the password. This means that even if two users have the same password, their hash outputs will be different because each hash includes a unique salt. This effectively thwarts attackers who use precomputed tables, known as rainbow tables, that map hashes to their corresponding plaintext inputs.

Salting increases the complexity for an attacker attempting to use a rainbow table, as they would need to generate a new table for each unique salt used, rather than relying on a single table covering multiple users or passwords. This practice significantly enhances security by ensuring that even if an attacker obtains a list of hashed passwords, they cannot easily reverse-engineer them using precomputed hash values.

The other options do not capture the main intent of salting. For instance, salting does not primarily focus on increasing the speed of hashing, making hash outputs longer, or simplifying the hashing process. Each of these aspects can be influenced by other techniques or methods outside of salting.