Why does the Swiss Signature Validator show a warning after QES signing with BoldSign?

BoldSign supports Qualified Electronic Signatures (QES) through Swisscom Trust Services, a certification service provider recognised under the Swiss Federal Act on Electronic Signatures (ZertES / ESigA ). This ensures your documents meet Swiss QES requirements and carry the same legal standing as a handwritten signature in the event of a dispute.

If a document signed with a Qualified Electronic Signature (QES) through BoldSign displays a warning in the Swiss Signature Validator, the warning is typically related to the additional document seal applied by BoldSign and does not affect the legal validity of the Qualified Electronic Signature.

Understanding the validation results

When you upload a QES-signed document from BoldSign to the Swiss Signature Validator (the eGov signature validator of the Swiss Federal Administration):

• You will see a valid Qualified Electronic Signature issued by Swisscom, along with a qualified timestamp confirming compliance with ZertES requirements.
• You may also see a warning or an overall result that is not fully valid because of the additional document seal applied by BoldSign.

Example validation results

Swisscom signature report

The validator confirms:

• A valid Qualified Electronic Signature.
• A valid qualified timestamp.
• Compliance with Swiss ZertES requirements.

BoldSign seal report

• The validator may indicate that the BoldSign document seal cannot be verified or is not qualified.
• This is expected behavior and does not affect the validity of the Swisscom QES.

Why does BoldSign add an additional seal?

After the QES is applied:

1. BoldSign certifies the final document using an Adobe Approved Trust List (AATL) trusted DigiCert document-signing certificate.
2. The seal helps protect the document against further modifications.
3. The seal supports long-term document integrity and validation.
4. The seal improves compatibility with Adobe Acrobat Reader and other PDF validation tools that trust AATL certificates.

The Swiss Signature Validator is designed to validate:

• Swiss qualified signatures
• Swiss regulated seals
• Swiss Government PKI signatures

Because the validator does not validate all foreign or non-Swiss trust chains, it may flag the DigiCert document seal as not verifiable.

• In some cases, the validator may also indicate that the original Swisscom signature does not cover the final version of the file. This occurs because the BoldSign seal is added after the Qualified Electronic Signature has been applied.
• The underlying signed content remains unchanged.

Does the warning affect legal validity?

• No. The Swisscom Qualified Electronic Signature remains legally valid under ZertES requirements even when the validator reports a warning related to the BoldSign document seal.
• The warning affects only the validation of the additional seal and does not invalidate the original Qualified Electronic Signature.

Frequently asked questions

Does the warning mean the Qualified Electronic Signature is invalid?

• No. The warning typically relates to the additional BoldSign document seal rather than the Swisscom Qualified Electronic Signature. The QES remains valid and legally enforceable.

Does the warning mean the document was modified?

• No. The warning does not indicate that the document has been tampered with. It typically indicates that the validator cannot verify the additional document seal using its supported trust model.

Why does Adobe Acrobat Reader validate the document while the Swiss Signature Validator shows a warning?

• Different validation tools use different trust frameworks. The Swiss Signature Validator focuses on Swiss-qualified signatures, regulated seals, and Swiss Government PKI trust chains. Adobe Acrobat Reader also recognizes Adobe Approved Trust List (AATL) certificates, including DigiCert document-signing certificates used by BoldSign.
• As a result, the same document may display different validation results depending on the validation tool used.

Is the Swisscom Qualified Electronic Signature still legally valid?

• Yes. Documents signed through BoldSign using Swisscom Qualified Electronic Signatures remain legally valid under ZertES requirements, even if the validator reports a warning related to the BoldSign seal.