A rainbow table is a precomputed table for reversing cryptographic hash functions, usually for cracking password hashes. Tables are usually used in recovering the plaintext password, up to a certain length consisting of a limited set of characters. It is a practical example of a space/time trade-off, using more computer processing time at the cost of less storage when calculating a hash on every attempt, or less processing time and more storage when compared to a simple lookup table with one entry per hash. Use of a key derivation function that employ a salt makes this attack infeasible.
Rainbow tables are an application of an earlier, simpler algorithm by Martin Hellman.
Read more about Rainbow Table: Background, Precomputed Hash Chains, Rainbow Tables, Defense Against Rainbow Tables, Common Uses, See Also
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