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Use LuxTrust to sign your PDF(s)!

Good news! You can use your LuxTrust electronic identity to sign your most important documents from home, in just a few clicks and without meeting in person your counterparts.

Designed in-house by LuxTrust, COSI Home Edition is an online service allowing anyone having a LuxTrust electronic identity (or a Luxembourgish eID card) and device to sign electronically a large variety of documents in a PDF format.

LuxTrust offers you 5 free electronic signatures every month to help you better manage your administrative chores during the confinement period.

Sign your PDF document in 4 easy steps!

1. Connect with your LuxTrust identity

Use your LuxTrust credentials and device (Token, Mobile, Scan, SmartCard ou Signing Stick) to connect to the service.

2. Upload your document

Define a name for your e-signature session and click on “Upload document” (PDF format, up to 15 Mb).

3. Place your signature (optional)

Click on “Place your signature” to choose where you want your signature to appear in the document.

4. Sign and download your document

Click on “Sign”, enter your credentials again and download your signed document.

Did you know?


Your electronic signature is not visible in the same way as a handwritten signature!

This is because an electronic signature is an unique code generated from your document (this is called a “hash”). This code combines a series of characters from your document as well as your certificate data with the date and time of signing.

The signature is stored in your document and ensures that your document has not been changed after signing. If you add even a space in your document, the signature will no longer be valid!

Also, if sometimes you do not see the image of the signature, it does not mean that the document is not signed. To check this, you can open it in a tool as simple as Adobe Reader DC.

Frequently asked questions

What is a LuxTrust electronic signature?

An electronic signature is a legal concept established in the EU regulation 910/2015 (shortly, eIDAS). It enables people to sign, approve and agree electronically a given digital document. According to eIDAS, there are three levels of e-signatures (simple, advanced, qualified). To learn more, click here. If you are equipped with a LuxTrust electronic identity and device, then the signature you generate has the highest level (qualified) meaning that it has the legal equivalent of a handwritten signature.

What happens if I used my 5 free e-signatures?

You can connect to the service, but will not be able to sign. Your credit will be automatically renewed at the end of each month. If you have recurrent business needs and want an easy-to-implement e-signature solution, check Simply COSI, a fast-deployable document management and electronic signature platform more adapted to business needs.

I cannot see my e-signature in the document. Is something wrong?

It may happen that the drawing/image representing your signature is not visible in the document. However, if you have completed your signature process, your document is duly signed electronically. Your electronic signature is not visible in the same way as a handwritten signature! You can check it by opening your document with Adobe Reader.

Can I use COSI Home Edition for my company?

You can use the service as long as you still have credit (e-signatures) available. For businesses, LuxTrust proposes various solutions more adapted to their needs. You can contact us here to find out more.

What are the technical requirements to use this online service?

There are no specific technical requirements for using this service, you just need a good Internet connection. For your security, we advise you to take all precautionary measures to protect your computer (such as install an antivirus, keep your system up-to-date etc.) and do not disclose your LuxTrust credentials (User ID and password) under any circumstance.

I am not a LuxTrust client. Can I still use COSI Home Edition?

The service is currently reserved for LuxTrust customers (including persons who have a Luxembourgish eID card). If you want to become one, you can get a LuxTrust electronic identity via video identification here.

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