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 End-User Documentation

Document Signing

This topic explains why it is necessary to sign a document and how this can be done using the PDF Document API component.

Expanded Overview

The PDF Document API allows you to electronically sign a document. A digital signature is used to help authenticate the identity of a user and the document's contents.

To sign a document, you need a digital certificate. The certificate is issued by a Certification Authority (CA). The role of the CA is to validate the holder's identity and provide access to a certificate.

To learn how to apply a signature to a document, refer to the How to Sign document section.

Expanded Prerequisite

Before signing, the PDF Document API component must have a document (e.g., you can load a document using the PdfDocumentProcessor.LoadDocument method).

Expanded How to Sign

Access a signing certificate.

You can either get it from a third-party certificate authority (CA) or generate the X.509 certificate with a private and public key pair using, e.g, the Makecert.exe (Certificate Creation Tool) for testing purposes only.

Create a signature and specify the signing information.

An electronic signature is represented by an instance of the PdfSignature object with the certificate. The signature can be accessed using the PdfSaveOptions.Signature property.

You can specify the signer name or organization name, signing location, reason, and contact information using the PdfSignature.Name, PdfSignature.Location, PdfSignature.Reason and PdfSignature.ContactInfo properties.

In addition, you can get a signing time using the PdfSignature.SigningTime property. This property is used to validate the signature.

Save a signed document.

To accomplish this task, call the PdfDocumentProcessor.SaveDocument method and pass the PdfSaveOptions object containing a signature as a parameter.

Expanded Example

The following example shows how to sign a document using the PDF Document API: How to: Add a Digital Signature into a PDF Document

Expanded See Also

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