A rainbow table attack uses large, precomputed tables that link hash outputs back to likely original inputs (typically passwords). Instead of storing every password→hash pair directly (which would be huge), rainbow tables store chains created by alternating hash operations with reduction functions, allowing attackers to reconstruct candidate plaintexts that produce a given hash. This makes cracking fast , if the target hashes are unsalted and use a known, fast hash function. Salt defeats rainbow tables because the attacker would need separate tables for each salt value, which becomes infeasible when salts are unique and sufficiently large. A dictionary at tack is related but typically computes hashes on the fly from a wordlist rather than using precomputed chain structures. A birthday attack targets collisions, not mapping to original data. Brute-force tries all candidates without precomputation. Because th e question explicitly describes mapping hashed values back to original data via a precomputed approach, the correct choice is Rainbow table.