Implementing advanced electronic signature by public digital identity system (SPID)

Advanced electronic signature is a form of signature recognized by EU legislation, which does not include the heaviest features of qualified electronic signature (i.e., qualified PKI certificates and qualified signature creation devices). The massive adoption of advanced electronic signature strictly depends on how solutions are easy, usable, and little invasive for citizens. In this paper, we propose a new advanced electronic signature protocol that relies on a public system for the management of the digital identity. Our proposal aims at implementing an effective synergy between the two mechanisms to provide the citizen with a unique, uniform, portable, and effective tool applicable to both peer authentication and document signature. The solution is designed for the Italian Public Digital Identity System (SPID), but it is easily extensible to any identity management system compliant with the EU regulatory environment (i.e., eIDAS).