PDF Digital Signature | Flutter PDF library

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Overview

PDF digital signature are the best ways to protect your PDF files from being forged. Syncfusion Essential PDF is a Flutter PDF library that helps you add digital signature to your PDF files in any Flutter application. Syncfusion provides many ways to digitally sign a document: X509 certificates, such as .pfx files with private keys and also supports hardware security modules (HSM), Online Certificate Status Protocol (OCSP), certificate revocation lists (CRL), and Windows Certificate Store for authenticity and integrity.

Customize Appearance

The Syncfusion Flutter PDF library provides a completely customizable appearance for its e-signature. The content of the signature can be images, texts, graphics, and shapes.

Custom Appearance

Additional features of digital signatures and timestamps

Sign existing PDFs with digital signatures.
Add multiple digital signatures to a PDF.
Externally sign a PDF document.

PDF Digital Signature Code Example

Easily add the digital signature to a PDF document using a few simple lines of C# code as demonstrated below. Also explore our Flutter PDF Example that shows how to create and modify PDF files from C# with 5 lines of code on different platforms.

c#
using Syncfusion.Pdf;

//Creates a new PDF document.
PdfDocument document = PdfDocument();

//Adds a new page.
PdfPage page = document.pages.add();

//Creates a digital signature and sets signature information.
PdfSignatureField field = PdfSignatureField(page, 'signature',
    bounds: Rect.fromLTWH(0, 0, 200, 100),
    signature: PdfSignature(
        //Creates a certificate instance from the PFX file with a private key.
        certificate:
            PdfCertificate(File('PDF.pfx').readAsBytesSync(), 'password123'),
        contactInfo: 'johndoe@owned.us',
        locationInfo: 'Honolulu, Hawaii',
        reason: 'I am author of this document.',
        digestAlgorithm: DigestAlgorithm.sha256,
        cryptographicStandard: CryptographicStandard.cms));

//Add a signature field to the form.
document.form.fields.add(field);

//Save and dispose the PDF document.
File('Output.pdf').writeAsBytes(document.save());
document.dispose();