According to the way the software works, once you select the ZIP file and check the Secure-Sign, a file will stored inside the ZIP or next to the file in form of sign.995 or securesign.995. When someone accesses the file, he will be prompted to co-sign. If you have issues with the software, I recommend consulting the original manual file where all the steps are provided. To do this, either browse the installation folder or go to Help > Contents.
