What is EVCK?

EVCK is a tool that implements a 2 out of 2 threshold extended visual cryptography scheme.
Born from the idea of G. Ateniese, C. Blundo, A. De Santis, and D. R. Stinson (Extended Schemes for Visual Cryptography) and for a seminar about it.

What does it do?


  • two looking innocent image I1, I2,
  • an image SI containing the secret.

Encode I1 and I2 so that we can obtain SI by stacking together their transparencies.


The only requirement to run EVCK is Java 1.4

How to obtain

Download it, unzip and refer to the README file for more information about executing.



EVCK is released under the GNU General Public License (GPL). See COPYING file in the packages for more information.


  • Extended Schemes for Visual Cryptography
    by G. Ateniese, C. Blundo, A. De Santis and D. R. Stinson,
    submitted to Theoretical Computer Science
  • Visual Cryptography
    by M.Naor and A. Shamir.
    the first about Visual Cryptography.
  • Visual Cryptography Kit (VCK)
    by F. Stajano