How to Sign OpenOffice and LibreOffice Documents?

Whether you’re sending a business proposal, a contract, or a research paper, no one wants to open a file and wonder, “Is this authentic?”

That’s where digital signatures come in.

If you’re using OpenOffice or LibreOffice, the good news is you don’t need to be a tech wizard to sign your documents securely. You just need the right steps.

Today, I’ll walk you through how to digitally sign OpenOffice and LibreOffice documents so your recipients instantly know they can trust your file.

Why Bother Signing OpenOffice or LibreOffice Documents?

Before you start clicking around menus, let’s talk about why this matters.

Digital signatures do two powerful things:

• Authenticate the sender – They prove that the file really came from you (and not some random impostor).
• Preserve integrity – They make sure no one tampered with your document after you signed it.

If you’re sending financial documents, legal papers, contracts, or even internal reports, a digital signature instantly adds a layer of professionalism and trust. And with OpenOffice or LibreOffice, the process is surprisingly simple. Before moving forward, ensure you have a document signing certificate from a trusted CA.

Steps to Digitally Sign a Document Macro using OpenOffice/LibreOffice

Step 1: Open Your Document

Start by opening the document you want to sign.

It can be a Writer file (.odt), a Calc spreadsheet (.ods), or even an Impress presentation (.odp).

Once it’s open, go to the menu bar at the top and click:

File → Digital Signatures

This is your gateway to the signing process. When you click that option, a dialogue box will pop up.

Step 2: Add Your Signature

Now, in the Digital Signatures dialogue box, click “Sign Document.”

This is where you’ll see all the available certificates that you can use to sign your file.

If you’re using a DigiCert token or any other hardware-based signing tool, you’ll see the certificates tied to your token right here.

Then, click Sign.

That’s it. You’ve just signed your document. When it’s done, you’ll notice something new. Your document title at the top will now say (Signed) right next to its name.

Step 3: Enter Your Token Password

In case your digital certificate is saved in a SafeNet device (the physical device supplied by DigiCert or other services), you will be asked to use your token password.

Imagine that this password is your virtual fingerprint. It makes sure that your certificate can be utilised by nobody but you.

The signature will be automatically applied as soon as you get there.

Click Close, and you’re done.

Step 4: Verify That Your Document is Signed

Looking at the title bar of the document you are in now, you now see your name in something like this:

Contract_Proposal.odt (Signed)

This is to indicate that your digital signature has been added successfully. Any person using this file in OpenOffice or in LibreOffice can instantly notice that it is signed and has not been interfered with.

In case one attempts to edit or modify it, the digital signature is invalidated. That is how you keep data intact and original without even raising an eyelid.

Step 5: View the Certificate Details

Want to see the details behind your signature? Here’s how:

• Open the signed file.
• Go to the right-hand panel and click View Signatures.
• A column will appear on the right side of the screen with a dropdown menu.
• Click Signature Details.

Note: Time Stamping vs. Signing

When you sign a PDF with Adobe, it’s often time-stamped automatically using systems like DigiCert’s timestamp server.

That means the signature includes a verified time of when the document was signed. However, in OpenOffice and LibreOffice, documents aren’t time-stamped by default.

Instead, they record two things:

• The local time when the signature was created
• The validity period of your certificate