Missing_Cells

My computer wanted to play sudoku, but it only knows binary. It gave me a 16×16 grid of 0s and 1s, and asked me to fill in the missing cells. Apparently, the solution will help me unmask a secret.

Can you help me solve it? I was told I should pay close attention to the format of the flag.

Secret: c56217e72f2ee27f0ec1f00f06956493ab02a2f8072159f3a27e79d399a4924f

Grid :

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0 . . . . . 1 1 . 1 1 . . 1 . 1 . . . 1 . . . . 1 . . 0 . . . . . . . 1 . . . . . . . . . . . 1 . 0 . . 0 . 0 . 0 . . . . . . . . . . . . . 0 0 . . 0 0 . . . . . . 1 1 . . . . . . . . . . 0 . 1 . . . . . . 0 . . 1 . . 1 . . . 1 . . . . 1 . . 1 1 . . . . . . . . 0 . . . . . . . . . . 1 . . . . . 1 . 1 1 . . . . . . . . . . . . . . . . . . . . . . 0 . . 1 . . . . . 0 . . . . . . . . . . . . . . . .

Flag format: PWNME{.........................}

Author : Mat