Digital Signature Examples
Signing a PDF takes a certificate, a document and a few lines of code, and a signing process around it takes much more: signers, signature fields, a viewer that collects the signatures and a server that applies the certificates. The examples below cover both, from the online demo that signs a single PDF to SignFabric, an open-source e-signature application built with TX Text Control. The samples load certificates as PFX files; Certificate-Based Signatures explains what the Core engine needs from a certificate.
Online Demos
| Example | What it shows | Where |
|---|---|---|
| Signing a PDF | An X.509 certificate applied to the whole document when it's exported as PDF | Digitally sign PDFs |
| Signatures from the Document Viewer | Signature and initials boxes signed in the viewer and each signature field signed with a certificate on the server | Electronic Signatures |
| Signature fields in the editor | A signature field with signer data inserted in the Document Editor and signed with an image, later in a PDF reader or with a certificate on the server | Signature Fields |
| SignFabric | The live installation of SignFabric for signers; the administration is tried out with a clone of the repository | esign.textcontrol.com |
The demos of the viewer that capture raw signature data and merge signature annotations are listed in Document Viewer Examples.
SignFabric
SignFabric is an ASP.NET Core application for preparing, sending, signing and validating documents. It combines the Document Editor, the Document Viewer and PDF signing with certificates from PFX files or Azure Key Vault, audit logging and an API for other applications. Licensed users of TX Text Control can run it in their own infrastructure.
| Example | What it shows | Where |
|---|---|---|
| SignFabric | The complete application, as described in Introducing SignFabric: An Open Source, Enterprise-Ready E-Sign Platform Built with TX Text Control. .NET 10, version 34.0 | SignFabric |
| First envelope | Cloning, configuring and running SignFabric, uploading a certificate and sending the first document for signature | Getting Started with SignFabric: From Clone to Your First Signature Envelope |
| API client | A console application that merges a template with signature boxes and creates a SignFabric envelope through its API, as described in Create SignFabric Envelopes from Mail Merge Templates in .NET C#. .NET 10, version 34.0 | TXTextControl.SignFabric.APICall |
Sample Projects
| Example | What it shows | Where |
|---|---|---|
| Signature fields with PFX certificates | Signatures collected in the Document Viewer and the signature fields signed with a PFX certificate in a controller, as described in Digitally Sign Signature Fields with PFX Certificates. Version 33.0 | TextControl.Web.MVC.Core.SignCertificate |
| Console signing | The whole document and individual signature fields signed in a console application, as described in Digitally Signing Adobe PDF Documents. Version 33.0 with the Classic engine | TextControl.Core.CommandLine.Signing |
| Angular | Electronic signatures in the Angular Document Viewer and digital signatures in an ASP.NET Core backend, as described in How to Add Electronic and Digital Signatures to PDFs in ASP.NET Core C# and Angular. Version 32.0 | TXTextControl.Web.Angular.Core.Signing |
| E-signing reference implementation | Documents created in the editor, sent to recipients, signed in the viewer and recorded in an audit trail, as described in E-Signing Reference Implementation in .NET C#: An Overview. Version 32.0 on .NET 6 with the Classic engine | TextControl.Web.MVC.ESign |
The Blazor sample that signs documents from the viewer component is listed in Document Viewer Examples.
Blog Articles With Code
| Example | What it shows | Where |
|---|---|---|
| Whole document or signature fields | The difference between signing a document and signing its signature fields | Understanding the Differences: Signing a PDF Document vs. Signing Signature Fields in a PDF in C# |
| Signing on Linux | PDF documents signed with a PFX certificate in .NET on Linux | How to Sign PDF Documents with PFX Certificates in .NET C# on Linux |
| Self-signed certificates | A certificate for tests created with PowerShell and used to sign | How to Create Self-Signed Certificates on Windows to Sign PDFs in .NET C# |
| Timestamps | Signatures with an RFC 3161 timestamp for long-term validity | Building Long-Term Trust with Digital Signatures and Timestamps in C# .NET |
| Signer information | Signature fields signed with custom signer data and a timestamp in ASP.NET Core | How to Sign Signature Fields with Custom Signer Information and Time Stamps in ASP.NET Core C# |
| Fields from MS Word | Signature fields of a DOCX document created in MS Word signed as PDF | Apply Digital Signatures to PDF Signature Fields Imported from MS Word in C# |
| Several signers | A document prepared for signatures of several people | Preparing Documents for E-Signing for Multiple Signers in .NET C# |
| Validation | The signatures and the integrity of a PDF checked with TXTextControl.PDF.Validation; the article uses a prerelease for .NET 8, while the current package targets .NET 10 | Validate Digital Signatures and the Integrity of PDF Documents in C# .NET |
Digital Signatures explains each of these tasks with the current code, and Digital Signatures in Security covers keys, signing endpoints and validation.
Next Steps
- Digitally Sign a PDF: sign a first document with a test certificate.
- Document Viewer Examples: collect electronic signatures in the browser.
- PDF Examples: create, protect and validate PDF documents.