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Digitally sign documents with an eIDAS certificate on Windows

With an eIDAS-compliant certificate from IONOS, you can provide your digital documents with a legally secure digital signature. Think of this signature as a digital seal. It confirms the authenticity of the sender and the integrity of the document, i.e. that the document has not been altered since it was signed.

In this article you will learn

  • How to import your eIDAS certificate into Microsoft Windows
  • How to sign PDF documents with Adobe Acrobat Reader
  • How to sign ODT and PDF documents in LibreOffice
     

Import eIDAS certificate into Windows

To be able to use your certificate in applications such as Adobe Acrobat or LibreOffice, you must first store it in the Windows certificate store.
 

Requirement

Step 1: Create certificate file (PFX) in the IONOS account
  • Log in to your IONOS account.
  • Click MENU > Domains & SSL in the title bar.
  • Navigate to the Portfolio tile to the right of the domain overview, and click on the Manage link in the eIDAS area. The overview of your eIDAS certificates opens.
  • Click on the name of the certificate for which you want to create the certificate file. The "Certificate Information" tab opens.
  • Switch to the Certificate Files tab.
  • In the Create and Download .PFX File area, click Download.
  • In the Private Key field, enter the private key that you received during the initial setup at IONOS account.
  • Set a password for the certificate file. This password protects the PFX file from unauthorised access, and is required when importing the certificate. Make a good note of it.
  • Click on Download PFX File.

The certificate file with the extension .pfx is now created and saved in your download folder. In the next section, we will show you how to import this certificate file into the Windows certificate store.

Step 2: Import the certificate file into the Windows certificate store
  • Open Windows Explorer and navigate to the location of the downloaded PFX file.
  • Double-click on the PFX file to start the certificate import wizard. Carry out the following steps in the wizard.
  • Select Current Useras the storage location and click Next.
  • Confirm the file name with Next.
  • Enter the password that you specified when creating the PFX file.
  • Select the desired import options according to your requirements. We recommend keeping the option Include all extended properties selected by default.
  • Click on Next.
  • Retain the option to automatically select the certificate store and click Next. You will receive a summary of the selected settings.
  • Click Finish to finalise the import.

The certificate is now stored in the system and can be used by your applications.

Sign PDF form with Adobe Acrobat Reader

Requirements

  • You have imported your eIDAS certificate into the Windows certificate store as described above.
  • You have installed Adobe Acrobat Reader on your computer.
     
  • Open the PDF form to be signed with Adobe Acrobat Reader.
  • Click on the All tools menu and select View more > Use a certificate.
  • Click on Digitally Sign in the submenu that opens. A dialogue opens in which you are asked to define the area for the signature.
  • Confirm with OK.
  • Use the mouse to drag a rectangular area in the document where you want your signature to appear.
  • Select your imported certificate in the dialogue that opens and click Continue. A preview of your signature is displayed.
  • Optional: Click on the Create button to customise the appearance of the signature. For example, by adding an image, or changing the information displayed.
  • Optional: Activate the Lock document after signing option. This ensures that the document can no longer be changed, which guarantees the validity of the signature.

Note

If the option to lock the document is not activated, the creator can edit the signed document again later. To do this, however, they must remove the signature and sign the document again after editing.

  • Click on Review to check the document content before signing.
  • Click on Sign.
  • Select a storage location and a file name for the signed document and click Save.

This completes the signing process. The signature should now be visible at the selected location in the document. Acrobat also displays corresponding information above the document for signed documents. To display further information on the signature, simply click on the signature.

Signing documents with LibreOffice

Requirements

  • You have imported your eIDAS certificate into the Windows certificate store as described above.
  • You have installed LibreOffice on your computer.
Method 1: Export document directly as a signed PDF (recommended)

This is the most common use case, for example, if you have created a letter or an invoice with LibreOffice Writer.

  • Open or create your document in LibreOffice (e.g. Writer).
  • In the menu, click on File > Export as > Export as PDF..
  • In the PDF Options dialogue window, switch to the Digital Signatures tab.
  • In the Certificate area, click on the Select... button
  • Choose your eIDAS certificate from the list and click Select.
  • Click on Export.
  • Select a file name and a storage location for your PDF file and click Save.
  • A dialogue box will open asking you whether LibreOffice should remember the signature for each save operation.
    • If you click Yes, the digital signature will be saved and automatically added each time you edit and save the document. This can be useful if you want to ensure that every version of the document is signed by you.
    • No: If you click No, the document will only be signed this one time. If you edit and save the document again later, the new version will not be signed automatically. You would then have to perform the signature process again manually.
      The document is now created as a digitally signed PDF file.

 

You have now saved your document as a signed PDF file.

You can then open the PDF file with LibreOffice to check the result. A note on signing should now be displayed in the info bar above the open document. Click on the corresponding button to display further information about the signature.

Method 2: Sign an existing PDF or ODT document
  • Open the document to be signed (e.g. .odt or .pdf) in LibreOffice.
  • In the menu, click on File > Digital signatures > Digital signatures...
  • If you are editing an .odt document that has not yet been saved, you will be prompted to do so. Save the document.
  • In the "Digital signatures" dialogue window, click on Sign document..
  • Select your eIDAS certificate and click on Sign.
  • Close the dialogue to return to the document.
  • A dialogue box opens asking you whether LibreOffice should remember the signature for each saving process.
    • If you click Yes, the digital signature will be saved and automatically added each time you edit and save the document. This can be useful if you want to ensure that every version of the document is signed by you.
    • No: If you click No, the document will only be signed this one time. If you edit and save the document again later, the new version will not be signed automatically. You would then have to perform the signing process again manually.

      The document is now created as a digitally signed PDF file.


The document is now signed. A note on signing should now be displayed in the info bar above the open document. Click on the corresponding button to display further information about the signature

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