What is "Salt" in IT?

Definition:

In the context of computer security, a "salt" is a random or pseudo-random value that is added to data before it is hashed, typically used in password storage. The primary purpose of using a salt is to enhance the security of password hashes, particularly against attacks like rainbow table attacks and dictionary attacks.

Here's how it works:

Hashing: When a user creates or changes their password, the system generates a random salt and combines it with the password. The combination is then hashed using a cryptographic hash function, resulting in a fixed-length string of characters that represents the password and the salt.

Storage: The hashed password, along with the salt, is stored in the system's database. The original password is not stored. This means that even if an attacker gains access to the hashed passwords, they won't be able to easily reverse-engineer the original passwords without knowing the salts.

Verification: When a user tries to log in, the system follows the same process. It retrieves the stored salt associated with the user, combines it with the entered password, hashes the combination, and then compares the resulting hash with the stored hash. If they match, the entered password is correct.

The use of salts provides several security benefits:

Unique Hashes: Salts ensure that even if two users have the same password, their stored hashes will be different due to the unique salts. This prevents attackers from identifying identical passwords across different accounts.

Protection Against Precomputed Attacks: Precomputed attacks, such as rainbow table attacks, involve using precomputed tables of hash values to quickly look up plaintext passwords corresponding to hash values. Salting makes these tables ineffective, as each hash is unique.

Mitigation of Dictionary Attacks: In a dictionary attack, attackers use a list of common passwords and their corresponding hash values to try to guess passwords. Salting makes this approach less effective since each password is combined with a unique salt before hashing.

Increased Complexity: The addition of a salt significantly increases the computational effort required for attackers to crack passwords, as they would need to compute hashes for each guessed password and salt combination.

Conclusion:

Overall, using salts is an important practice in password security to enhance the protection of user credentials and make it more difficult for malicious actors to compromise accounts through various forms of attacks.