We're sorry Aspose doesn't work properply without JavaScript enabled.

Free Support Forum - aspose.com

Email add check signature .NET

Dear Aspose,

we are currently searching for a component that is able to add and verify Signatures in common office file types wihout having to install Office software. (doc, docx, xls, xlsx, msg, pst, pdf).

The word and cells .NET libraries have a Boolean propeerty IsValid. Which is good if its true. But when it is false I dont know why ? (certificate expired, document modified, invalid key usage, etc…)

Are you planning to extend the validation functionality in the near future or should we look for another component?

The second question is about adding and validating email message signatures. Does the Network .NET component have a funcionality for this? Or a plan to add this in the near future.

With best regards

CNS Developer


I am a representative of Aspose.Cells. We do provide functionality to assign and validate digital signatures for Excel spreadsheets. The product does provide valuable properties for DigitalSignature class, e.g. IsValid, SignTime, Comments etc. See the document for reference:

Could you elaborate what kind of functionality/features you want when IsValid returns “false”. You may also give us some sample files to explain it more. We may look into it.

Thank you.


Thank you for inquiry.

I represent Aspose.Network. Regarding the certificates in email, you can check whether an email contains a certificate or not using MailMessage.IsSigned property.

MailMessage msg = MailMessage.Load(“test.eml”, MessageFormat.Eml);
Console.WriteLine("Is signed: " + msg.IsSigned + “\n\n”);

For adding certificates to an email, I have found an issue and logged it in our bug tracking system (ID: 25331). We will inform you as soon as it gets fixed.

Hi Martin,

I represent Aspose.Pdf.Kit and I would like to share with you that Aspose.Pdf.Kit for .NET allows you to sign a PDF file; it also allows you to verify the signature. In addition to that, you may get the signature information and its attributes as well. Please see the PdfFileSignature class for the related methods and properties.

Please also have a look into the following article to understand the PDF signing mechanism:
Improved and Flexible PDF Signing Mechanism.

I hope this helps. If you have any further questions, please do let us know.

Hi there,

Thanks for your inquiry.

As you may know Aspose.Words allows you to verify a signature on a loaded document. For further details please see this article here. I'm afraid currently there is no way to get the details as to why the verification failed. I have logged your request for this.

You can however access the 509Certificate2 object by using the DigitalSignature.Certificate property. This could be used to analyze why a certificate failed to verify.