![](https://ip.bitcointalk.org/?u=http%3A%2F%2Fwww.dailysudoku.com%2Fsudoku%2Fmonster%2Fpng%2F2012%2F12%2F2012-12-29_solution.png&t=665&c=vkAqRthaCI1lSA)
Although not knowing what the demographics are of Sudoku solvers, I fathom to guess that many are up in their years. There are a myriad of Sudoku puzzle books on the market, all having the solutions in the back. All that a person would have to do is have access to only one of those books, selecting any solved puzzle in the back to glean a password from. Even if they lose the book, as long as they somehow remember the books title, its edition number, or ISBN, they should have no problem getting another copy. The safest solution is to hide several copies of a solution page.
From the image above, a 70-year-old woman would have 64 easy passwords to chose from: 16 rows left-to-right; 16 rows right-to-left; 16 columns top-to-bottom; 16 columns bottom-to-top. Thus, the first password would be 16A4BFCE8975302D.
In fact, one doesn't even to purchase a book. Simply go to
http://www.e-sudoku.fr/sudoku16x16.php and generate a random solved puzzle from there like below, where the first password choice would be ADF58B314G67C92E.
![](https://ip.bitcointalk.org/?u=http%3A%2F%2Ffarm9.staticflickr.com%2F8212%2F8324554442_fca964dd5a_z.jpg&t=665&c=jYri1nEg9aUyeg)
I just realized that there's 16 inner grids from which another 64 easy passwords could be cleaned, the fist being ADF5C8G79462BE13.
A hacker would need to know that Sudoku was used to generate a password, after somehow determining that a minimum amount of bitcoins protected would be worth their efforts to steal.
~Bruno K~