In my organization we have a different problem. We heavily use signed pdf files for all our internal documents - if a document is not signed it's not valid (the

In my organization we have a different problem. We heavily use signed pdf files for all our internal documents - if a document is not signed it's not valid (they are mainly signed with JSignPdf). A number of internal applications need such signed files in order to proceed with a workflow. Checking if a PDF file has been digitally signed, how many signatures are there and if the signatures are all valid is not an easy task! Actually, I only know how to do it in java using bounty castle. To help non-java apps with this I've implemented a small java application that provides a REST (and form) api for uploading a signed PDF file and returning information about the signatures. It works in my organization for more than 3 years and it's has saved us from hundreds of erroneously signed PDF files! I've open sourced it for anybody having similar requirements: https://github.com/spapas/pdf-sign-check https://github.com/spapas/pdf-sign-check.