Knowledge of the pattern has nothing to do with it. That 2048^4 figure is what I mean when I say such a password is strong, and such a figure presumes the attacker knows what system I am using.
Recall that since the passphrase is randomly generated, that 2048^4 is the true probability of guessing it--all the elements of the set are live possibilities. To compete on equal footing, a seven character password must also be randomly generated.
A password is not necessarily strong simply because it spans a large character set. "Sp1d3r!", for example, may as well be a dictionary word. Raw length "spiderspiderspider" is not necessarily helpful either. Randomness is what you need.
Recall that since the passphrase is randomly generated, that 2048^4 is the true probability of guessing it--all the elements of the set are live possibilities. To compete on equal footing, a seven character password must also be randomly generated.
A password is not necessarily strong simply because it spans a large character set. "Sp1d3r!", for example, may as well be a dictionary word. Raw length "spiderspiderspider" is not necessarily helpful either. Randomness is what you need.