Confusion over P versus NP

I am sure that in my next question my reasoning is extremely simplistic and flawed, but I think that if someone answers this, it would help me understand what the riddle P vs. NP is. This is my question: Why is the following not proof that NP is not equal to P?

Scenario: a computer receives a number of n digits that it must guess. The digits of this number were chosen at random. Since the digits are chosen at random, there is no pattern for a computer to detect and, therefore, simplify the problem. You must try all the solutions, of which there are 9 ^ n.

Does the problem with my reasoning lie in the assumption that the numbers are truly random? Is randomness impossible and there will always be an underlying pattern of how seemingly "random" numbers were chosen