Learn in the textbookAttacks Targeting Passwords and Authentication
DefinitionA brute-force attack (ブルートフォース攻撃) is an exhaustive search (総当たり) that works out a password by trying every combination of the usable characters in turn.
ExplanationBecause it does not narrow its candidates, it reaches the correct password eventually if given enough time. With n usable characters and a length of k, the number of combinations is n to the power k (k factors of n multiplied together), so the attempts rise steeply as the length or the character set grows. A mechanism that temporarily disables an ID after a set number of consecutive wrong entries is called account lockout (アカウントロック).
AnalogyIt is like opening a three-digit combination lock by turning it through every number from 000 to 999.
Memory hook“Brute force” means sheer force: the attack wins by numbers rather than by clever guessing.