I have stumbled upon the same difficulty in many companies, considering releasing and approval of project documentation. I am sure that many project managers and quality managers out there have experienced the never ending printing, signing and paper shuffling before project closure or regulatory appliance. There are many tools out there but mostly they cost too much (Continuous cost around 200USD/user/license/year) or are difficult to install/use. The free tools that I have found as pgp and PDF signing are focused on secure email or single signing, rather than the needed functionality for project/quality management (audit trail, approval process, and multiple signatures).

I am sure that a lot of people have searched or evaluated different solutions, rather than reinventing the wheel over again. I would like to invite everyone to put recommendation or comments here.

We are evaluation some of the well known tools such as docusign and ecosign and other free solutions such as PGP, easy signature and ejbca.   Our Aim is to put in place procedures, etc to be compiant. (Example FDA CFR Part 11).