Flutter Guides Digital signatures

Digital Signatures

Starting with 3.2.0, ComPDF Flutter SDK supports certificate-based PDF digital signatures. Applications can sign fields using PKCS#12 certificates, read signer information, and separately check signature validity, document integrity, and certificate trust.

Digital and image signatures serve different purposes. An image signature displays a signing appearance; a certificate-based digital signature also provides verification information. Configure text, images, colors, and layout for the visible appearance.

Key Capabilities

• Certificate management: Generate certificates, check passwords, read metadata, and add trusted certificates within the application.
• Document signing: Obtain an unsigned field, configure the certificate, reason, location, appearance, and permissions, and write a signed copy.
• Reading and verification: List signatures and certificates, and check document modifications, certificate trust, and expiration.
• Timestamps and long-term validation: Add signature timestamps, inspect LTV material, and supplement certificate chains and revocation information.

Workflow

Prepare a certificate, open the document, and obtain or create a signature field before signing. After success, open the output copy to read and verify the signature. Timestamps and LTV material collection also require the appropriate services, trust anchors, and network access.

Check signature validity, certificate trust, and timestamp status separately. Material readiness alone does not mean every signature passes long-term validation. See the corresponding guides for result fields and failure handling.

Guides

Certificate Management

Generate and load PKCS#12 certificates and manage application-level trust.

Create Digital Signatures

Obtain a signature field, configure its appearance and permissions, and write a signed copy.

Read and Verify Digital Signatures

Read signature information and check document integrity and certificate trust.

Timestamps and Long-Term Validation

Add timestamps and inspect or supplement long-term validation material.