SESKStuff Everyone Should Know
SESK: Stuff Everyone Should Know · sesk.info/secplus-salt-purpose

Adding a unique random salt to each password before hashing mainly defends against what?

Precomputed lookup tables, because every user's hash becomes unique.

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  1. Precomputed lookup tables such as rainbow tables ✔
  2. Shoulder surfing
  3. Phishing emails

Why: Without a salt, two users with the same password get the same hash and attackers can use one table for everyone. A unique salt forces them to crack each hash separately.

Huh, didn't know that: OWASP notes that with unique salts, nobody can tell whether two users share a password without cracking both hashes.

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Salt makes every password hash different. Chefs and security teams agree it improves the dish.
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References

Answer: Precomputed lookup tables such as rainbow tables. Without a salt, two users with the same password get the same hash and attackers can use one table for everyone. A unique salt forces them to crack each hash separately.

  1. OWASP Password Storage Cheat Sheet cheatsheetseries.owasp.org/cheatsheets/Password_Storage_Cheat_Sheet.html
    A unique salt must be added to each password to prevent attackers from using precomputed lookup tables like rainbow tables.
    Checked 2026-10-10.

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