What is the number of possible keys of 56-bit length if humans type the key on a keyboard using 8-bit ASCII printable characters? assume that there are a total of 95 printable characters that can be typed using a standard US English language keyboard. Repetition are allowed, that is, the same character an be typed more than once.

Hint: Use the formula N^r, where N is the number of things to choose from, and r of them are chosen on each trial. Repetition are allowed, that is, the same character can be typed more than once.