True or false: "There is fundamentally only one type of brute-force attack."

Question

Accepted Answer

False — there are two fundamentally different brute-force attacks: exhaustive key search and table lookup. They sit at opposite ends of the time-memory spectrum.

Exhaustive Key Search
Table Lookup

Type
Known-plaintext attack
Chosen-plaintext attack

Time
$k$ (test every key)
1 (instant lookup)

Storage
1 (negligible)
$k$ (store every result)

When it runs
During the attack (online)
Precomputed before attack (offline)

The key distinction:

Key search trades time for zero storage — you grind through keys one by one
Table lookup trades massive storage for zero online time — you do all computation upfront

And there's a third category: The Time-Memory Tradeoff (TMTO) sits between them, using $k^{2/3}$ of each. Meet-in-the-middle is a specific TMTO technique (not to be confused with man-in-the-middle, which is a completely different network attack).
Go deeper:

Brute-force attack (Wikipedia) — key search vs precomputed tables.

	Exhaustive Key Search	Table Lookup
Type	Known-plaintext attack	Chosen-plaintext attack
Time	$k$ (test every key)	1 (instant lookup)
Storage	1 (negligible)	$k$ (store every result)
When it runs	During the attack (online)	Precomputed before attack (offline)