OpenSignature is a project for the digital signature of documents. It works with all cards supported by OpenSC, and focuses on adding support for cards from accredited Italian CAs. The goal is to provide the first single product capable of supporting cards from multiple vendors/countries. This contrasts the approach taken by card vendors/providers whose software follows an exclusive single-vendor approach. OpenSignature attempts to make a major contribution to interoperability in the digital signature domain, and aims to greatly facilitate the setup of public access points that are currently the objective of several projects in Italy.