This query pertains to both XSSF and HSSF type Excel files. I have been struggling to figure out how to
a) Detect that a XLS / XLSX file has been digitally signed. and b) Extract information about the signature I see classes like PackageDigitalSignature and PackageDigitalSignature manager (at least for the openxml4j files). However after a fair amount of reading of the documents and search I am unable to figure out how to use them (or other associated classes) to achieve the two objectives I laid out above. Any assistance / pointers to information that I could further build upon would be greatly appreciated. Dhananjay
