# Explanation of part of a visual cryptography algorithm

I have been working on a project involving visual cryptography and I am stuck with the following problem.

My question is related to this paper, AN IMPROVED VISUAL CRYPTOGRAPHY SCHEME FOR SECRET HIDING, by R.Youmaran, A. Adler, A. Miri.

Can someone explain how one obtains the values for the matrix $O_{11}^{1'}$? Which can be seen in Figure 1 in the paper linked above. If possible, a step by step procedure would be appreciated.

## migrated from security.stackexchange.comJul 22 '15 at 20:26

This question came from our site for information security professionals.