Hi Pierre,
Thanks for your reply.
According to your last email, you said it threw the error "export private key failed" when you signed your PDF file with certificate from hardware token under .Net Core environment. I got a message from our Dev team, kindly note that there is no such an error information(export private key failed) in .NET Core 2.0 package of Spire.Pdf_5.12.19 , thus we guess the package you are using now may be an old version but not the latest one which I offered you via email last time. Please check the package version in your project, attach the download link of Spire.Pdf_5.12.19 again:
http://www.e-iceblue.com/downloads/TempVersion/spire.pdf_5.12.19.zip.
And below is the .NET Core dlls information for checking:
Spire.pdf.dll V 5.12.19.2420
Spire.License.dll V 1.3.8.320
By the way, have you tried the project I offered you via email? How does it run on your side?
Best wishes,
Amber
E-iceblue support team