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ZapSign and Adobe Reader Validation

In addition to using ZapSign's Authenticity Checker, you can also validate the integrity of documents in Adobe Reader.

Documents signed at ZapSign are certified by ZapSign with a A1 ICP-Brasil digital certificate, providing an additional layer of proof of the document's integrity.

Adobe Reader Validation

For documents signed after 20/07/2023, the procedure below is not necessary.


The Adobe Reader software does not recognize digital signatures made by A1 digital certificates issued by ICP-Brasil by default. For this reason, Adobe Reader may alert the user that the ZapSign signature is invalid or unknown.

To resolve this issue, it is necessary to import and define the certificate chain of the Certisign Certification Authority as one of the trusted sources in your Adobe Reader.

Note: The following step-by-step instructions are only an optional configuration for Adobe Reader installed on your computer. In any case, the ZapSign document is correctly signed and its integrity is guaranteed. The message reported by Adobe Reader is solely due to the lack of the Certisign certificate chain in your Adobe Reader. If you do not want to follow the step-by-step procedure, validate your document using ZapSign's authenticity verifier.

Step-by-step instructions for configuring Adobe Reader:

  1. Download the certificate chain of the Certisign Multiple Certification Authority G7 by clicking here or through the link http://icp-brasil.certisign.com.br/repositorio/ac_certisign_multipla.html
  2. Import the certificate in Adobe Reader.
    1. Open Adobe Reader and click on "Edit" and "Preferences".
    2. In the left menu, click on "Signatures", "Identities and Trusted Certificates", and select "More".
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In the "Trusted Certificates" section, click on "Import...". Click "Browse" and select the file downloaded in step 1.
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In the "Identities" section, click on "AC Certisign Multipla G7". Then, in the "Certificates" section, click on the item that has also appeared with the name "AC Certisign Multipla G7". Click on "Trust..." and activate the options "Use this certificate as a trusted root" and "Certified Documents". Finally, click on "OK" and "Import".
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Restart Adobe Reader and open a document signed with ZapSign. Your Adobe is now configured and ready to correctly validate signatures based on certificates issued by entities subordinate to the Brazilian Root Certification Authority. The result should be as follows: 

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