Securing A Database - License Key

[cheekybuddha]

Thanks for the video Uncle Gizmo. I thought I'd take a quick peek for 5 minutes and before I knew it I'd watched the whole thing.

Shame Brumgbach didn't expand on his work into the odd and singly even magic squares. Now I'm going to have to dig out his paper!

Oh well, there are worse things to do in lockdown!



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[gemma-the-husky]

I just revisited this thread, while looking for posts about securing a database. I scanned through the very interesting magic squares video that was posted earlier, and will have a longer look at that in due course. I don't think the Professor dealt with odd number magic squares, but they are easy.

Thanks for the link @Uncle Gizmo

Say a 5 x 5 square, with numbers 1 to 25.

Start with no 1 in the square under the centre, and successive squares move down and right 1 square, moving to the top of the next column if necessary. See 01 to 05 below When your next square is already used, instead of moving right and down, move down 2 (down and down), but just for the next square. See 06 to 10 in red. With this method, a main diagonal will always be the central terms of the number block - see 11 to 15 in green. The full square is below.

11 24 07 20 03
04 12 25 08 16
17 05 13 21 09
10 18 01 14 22
23 06 19 02 15