How to sign a PDF using iText and iTextSharp

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OpenSignature is an open source 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 of the project is to provide a 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 thus 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. Moreover, we hope that the peer-review of the open source approach will allow us to at least match the security level of competing single-card software.