Brute Force Attack
A brute force attack is a method of breaking some type of encrypted data which is usually a password or digital key. It attempts to use a large number of possible answers to the question by guessing answers. Then the attacking program will encrypt its guess using the same method the original encrypted data was encrypted with. Once it finds a match, it will have the encrypted data.
When choosing key lengths, the length of the keys should be set long enough to prevent a potential attacker with specific resources from being able to break the key with a brute force attack in a useful period of time. Likewise, many times passwords are salted with additional added values at the end of them to prevent them from being susceptible to a brute force attack.