Rethinking complex signature workflows: automated, secure and eIDAS-compliant

The audit trail provides a complete, admissible-in-court history of the entire signature process. It documents when and by whom the document was viewed, approved, and signed, including the verification method used (e.g., two-factor authentication or qualified eID). This log serves as primary evidence during audits or legal disputes that the signature was properly created.

Yes. When multiple people sign a document one after another (sequential workflow), the PDF contains a history of what are known as revision states. A validation tool (e.g., sproof Validate) validates each signature individually against the state of the document that existed at the time of each signature.

Standard signatures often can no longer be validated correctly after the underlying certificate expires (usually after 2 to 3 years). sproof sign therefore consistently uses the LTV (Long-Term Validation) standard. In this process, revocation information (such as CRL or OCSP lists) is embedded directly into the document at the time of signing. This allows the validity of the signature to be verified in an audit-proof manner—even decades later—and independently of the issuer.

As soon as a PDF document is altered even slightly after a digital signature has been applied, the cryptographic chain of seals is broken. Any professional verification tool will immediately report that the document has been tampered with and that the signature is therefore invalid. With sproof, because it is deeply embedded in the PDF, it is possible to precisely trace whether any changes were made in violation of the rules and, if so, which ones.

This message usually appears when the document has been signed using a tool whose root certificate is not included in the EU’s EUTL list or in the local Windows/Adobe certificate store. Although the document’s integrity may remain intact, its status as a legally valid “Qualified Electronic Signature” (QES) is thereby invalidated.

Yes, provided that the signature supports the LTV (Long-Term Validation) standard. For LTV-enabled signatures, all necessary certificate revocation information is embedded directly into the PDF at the time of signing.

No. You don’t need a credit card to start the sproof sign Business Trial. All you have to do is fill out the registration form. Our experts will then set up your trial account and personally guide you through the next steps so you can get started quickly and successfully.

Yes. You can try the Business Trial for free for 14 days. There are no charges during the trial period.

The Business Trial is designed for businesses and provides full access to all features for 14 days, including API test tokens, team features, and professional support. The Free License is permanently free and intended for personal use by individuals.

The model is continuously synchronized with the latest API documentation and the current compliance guidelines.

The sproof AI Consultant provides support with, among other things: API structure questions, understanding integration options, technical workflows, authentication and signature processes, architecture decisions around sproof Sign. He serves as an additional level of knowledge and support during the entire integration process.

No. It shortens the path to a solution. Our technical consultants are still personally available for highly complex, individual enterprise requirements.