Implementation and testing on (n*n) images:

1.Naor & Shamir - Visual Cryptography Naor, M., & Shamir, A. (1994, May). Visual cryptography. In Workshop on the Theory and Application of of Cryptographic Techniques (pp. 1-12). Springer, Berlin, Heidelberg.

doi : https://doi.org/10.1007/BFb0053419

2.Lin et al. - Flip Visual Cryptography Algorithm Lin, S. J., Chen, S. K., & Lin, J. C. (2010). Flip visual cryptography (FVC) with perfect security, conditionally-optimal contrast, and no expansion. Journal of Visual Communication and Image Representation, 21(8), 900-916.

doi : 10.1016/j.jvcir.2010.08.006