What is the difference between signature validation in WebNotarius and proCertum SmartSign versus Adobe Acrobat Reader?
Validation (verification) of an electronic signature can look different depending on the tool. Adobe Acrobat Reader shows the status of signatures directly in the PDF file, but is sometimes sensitive to the configuration and timeliness of trust lists - hence the famous „yellow question mark.”. WebNotarius (web application) and proCertum SmartSign (desktop application) use the verification mechanisms of the qualified trust services manufacturer and usually present the results in a more „technical” way, with clear certificate and timestamp status.
Below: quick picks, a comparison, the most common pitfalls, and brief instructions.
Which tool to choose?
- Adobe Acrobat Reader - when you want readily view status in thereby PDF and you show the result to non-technical people. Condition: correctly configured trust and up-to-date lists.
- WebNotarius (web) - when you need fast, reliable verification (without installing the application) and a legible report to attach (e.g., for correspondence with the contractor/office).
- proCertum SmartSign (desktop) - when you combine signing and verification, you work with many formats (PAdES/XAdES/CAdES) and you want to be in control as well offline.
Comparison in a nutshell
Criterion | Adobe Acrobat Reader | WebNotarius (web) | proCertum SmartSign (desktop) |
Tool | PDF viewer with PAdES verification | Validator accessible via browser | Signing and verification application (2-in-1) |
Formats | PAdES (PDF) | PAdES/XAdES/CAdES | PAdES, XAdES, CAdES |
Presentation of the result | Icons/banners in PDF („green hook, ” „yellow sign”) | Clear, descriptive technical report | Detailed windows and reports |
Sources of trust | Local settings and letters on | Current letters on the service side | Current letters in the app |
Timestamp / LTV | Read and status in PDF (configuration dependent) | Clearly described in the report | Clearly described in the report |
Strengths | Immediately in PDF, universality | Zero installation, clear report | Full control, working with multiple formats |
When to use | Quick preview in PDF | Quick secure verification and export of the result | When you combine signing and validation |
What do these tools actually check?
- Identity of the signatory - Certificate data (name/name, serial number, issuer, validity period).
- Integrity of the document - Whether the file was not altered after signing.
- Certificate status - Whether it was not invalidated (OCSP/CRL) and whether it was valid at the time of signature.
- Time stamp (TSA) - confirms the moment of signature; key to LTV (long-term verifiability).
- Chain of trust - Whether the certificate refers to a trusted qualified provider (QTSP) and current lists.
We write more about LTV and the practice of attaching a time stamp:
– How to verify a signature... (guide)
– Verification of qualified signature - authenticity
Why do you see a „yellow question mark” in Adobe?
Most common causes
- Outdated trust lists or lack of acceptance of the certification chain,
- missing or incorrect LTV data embedded in the signature (e.g., no OCSP/CRL from the time of signature),
- The differences in validation policies between Adobe and dedicated tools.
Remember, however, that
“Graphics / Stamp” in PDF is just a graphic. Validation is determined by cryptography and chain of trust
In the PDF, you can see a graphic stamp/banner (e.g., a green tick or yellow question mark). This visual interface layer program (e.g., Adobe), which is sometimes misleading because it depends on the local configuration and the validity of the trust lists.
Practical conclusion
A yellow mark is not a judgment. Do a cross-validation in WebNotarius or SmartSign and check the timestamp.
The most common mistakes and how to avoid them
- No timestamp → Include TSA with every signature (it's a viable LTV „insurance”)....
- Outdated trust lists → Update regularly; if in doubt, verify additionally in WebNotarius/SmartSign.
- Read only in Adobe →. At the „yellow sign” always make cross-validation In WebNotarius or SmartSign.
- Confusing validation with „stamp” in PDF → decides cryptographic status and chain of trust, not graphics.
- No validation report → for important matters (offers, annexes, minutes) keep the validation report.
Helpfully, we encourage you to take a look:
– Guide: how to verify a signature
– How to verify the authenticity of a qualified signature
Best practices from podpisano.pl
No matter what, remember good practices (link)
- Verify first, then add more signatures.
- Always include a time stamp (TSA) - it's „insurance” for years.
- Agree on a signature policy (co-signature vs. countersignature) and stick to the procedure.
- When the stakes are high, validate in at least two tools.
FAQ
Does the „yellow question mark” in Adobe mean an invalid signature?
Not always. Often it's a trust/configuration issue. Do cross-validation and check the timestamp. → Yellow sign article
Are WebNotarius and SmartSign „more reliable” than Adobe?
These are different engines and different presentation of results. Dedicated tools (WebNotarius or SmartSign) tend to give a more detailed report, which is sometimes helpful evidentially.
Does the signature alone suffice for LTV (Long-Term Validation)?
No. What is needed is timestamp and appropriate OCSP/CRL at the time of signature. → Validation guide
Can I validate offline?
Adobe and SmartSign can read embedded PDF data for verification. Online access is required for full status verification (when data is missing).
Summary for the busy
- Adobe: quick PDF preview, but dependent on configuration.
- WebNotarius: web application, clear report for dispatch.
- SmartSign: full control, also offline, all popular formats.
- Always add TSA and keep reports. „Yellow sign” cross check.
- The validity of the signature is determined by cryptography, chain of trust, OCSP/CRL i timestamp.
- When you need clear, technical result i report, reach out to WebNotarius or proCertum SmartSign.
Expand on the topic in our materials:
– How to verify the signature...
– Authenticity of qualified signature
– Yellow question mark in PDF
– Countersignature or second signature?
Qualified signatures SimplySign and Certum Mini
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