Re^3: Challenge: Hidden Message

[diotalevi]

It's just making a regex like \A[^\n]*(\w)[^\n]*\n(?:[^\n]*\1[^\n]*\n)+\z which just says, I captured $1 and it has to exist on every line. Higher # versions just capture more and assert the new digits, in order. It's really very simple. rx() could be improved if you pegged certain captures with specified characters. I'm searching the entire space so I'm slower.

What's this have to do with ATM PINs?

[Limbic~Region]

diotalevi,
The riddle setup is along the lines that when the website asking for your PIN does so, it will ask for it by creating a larger PIN and place the true values in positions W, X, Y, and Z (which change each time). You are then free to fill all the remaining positions with random numbers. The riddle itself is to determine the PIN after capturing a certain number of succesful logins. Forget I said ATM as this was web banking.