If you had long enough or fast enough, brute force attacks can function.

This would be described as a standard brute force attack.

A brute force attack taking 1 μs for each try, through all possible key words, would take around 300,000 years, on average.

It merely means that a brute force attack can't be used against it; right?

A brute force attack then appeared to be possible.

So the only reasonable attack would be some sort of brute force attack.

There are other factors that can be potentially used to speed up a brute force attack.

No one's going to do a brute force attack on you in that length of time.

Due to step 3, a brute force attack needs to test only 2 possible keys.

Common passwords can be guessed in a brute force attack.