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Tutorial: How to sign electronically a PDF document using your SmartCard

One of the uses for your electronic identity (eID) is to sign electronically a PDF document, that is to give your consent or approval of the term and conditions of a contract using electronic signature. This may not be a straightforward experience, especially if you have not done it before. So we will show you how to do it step by step.

Before we start, we need to set some terms straight. In this article, we speak of “electronic signature” as understood or defined in EU eIDAS regulation. The guidelines below address people equipped with a LuxTrust electronic identity which enables them to sign at a qualified level, the only one having the legal equivalent of the handwritten signature. Nonetheless, the steps may be similar to signing using eIDs from other providers.

Electronic signing: the basic requirements

There are a variety of ways of signing, softwares and document formats available, but we will focus on the most common situation – signing electronically a PDF document. Here is what you need before you start:

1. As mentioned, you need your eID, which implicitly means you are already equipped with a hard device or app. For this case, you will need your SmartCard supplied by LuxTrust.
2. Make sure your Smartcard is connected to your PC. For that, either insert it in the dedicated slot of your PC or into your SmartCard reader.
3. You need access to a computer equipped with a PDF reader, the most common one being Adobe Acrobat Reader, which is also available to download here.

How does it work?

1. Open the PDF file to sign in Adobe Acrobat Reader. For demonstration purposes, we have created a sample file.

Sign electronically a PDF document


2. Go to Tools tab and in Forms & Signatures section (do not be afraid to scroll a bit down), choose Certificates.

Sign electronically a PDF document


3. A new Certificates sub-menu will appear. Click on Digitally sign. A small message may appear asking you to draw the area where your signature will be.

Sign electronically a PDF document


4. Click and drag the mouse to select an area where you want to apply your signature (do the same movement as selecting multiple objects on a desktop).


5. A new window will pop up asking you to select your digital ID. Press Continue. If, by any chance, you have multiple eIDs, the program allows you to choose which one you want to use.

Sign electronically a PDF document


6. Now you get to preview how your signature will look like. If you do not fancy your “signature look”, you can personalise it using the Create button.

Sign electronically a PDF document


7. Click on Create. You can type your name in different fonts, draw with the mouse your signature or even upload an image of your signature or a logo. Then you can choose to include other features like, date, location etc. Once you are ok with the looks, click Save and then Sign.

Sign electronically a PDF document


8. Adobe will immediately ask you to Save As the newly signed document.


9. Before completing the saving, you may need to introduce your secret, personal pass code of the hard device (SmartCard) as a matter of security.

10. Congratulations, you are done! Your signature is visible in the area you have previously selected with the mouse.

A word on Fill & Sign option

When opening the file in Adobe, you may have noticed these icons Fill & Sign or Sign electronically  on top of the page or on the right side bar. If you hover over with the mouse, they suggestively inform you that you can “Sign document by typing or drawing a signature”.

You may be wondering why we did not use it to sign electronically. Indeed, this option allows you to create what looks like a signature in the document, but that signature is a basic one which provides with very little assurance in case of litigation. Following the process we have shown you, you will apply an electronic signature based on a qualified certificate using your eID enjoying the highest level of assurance and acceptance in European Union. It means that your electronic signature “weighs” as much as your handwritten signature.

So, this is who you sign electronically a PDF document using a Luxtrust SmartCard! How did you find the process?

You can also use other hard devices (such as the Token) or the LuxTrust Mobile app to sign electronically documents, but this is a rather a different process. We will show in one of the next posts how you can do it, so stay tuned…

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