I am trying to insert a signature (image of an actual signature) which I can use on LO documents and spreadsheets. This is intended to give some measure of confidence that the document is the one that has been signed and warns those reading it if it is amended. A brief description of the process is given in the LO documentation.
I shall be trying this out but one issue that comes to mind is that a signature requires a CA certificate. Where and how do I get one of these and is there a way of keeping the secure part secure in, for example my KeepassXC password manager?
If I sign a document when it has been completed will the signature work if saved as a pdf. I ask because many addressees will be using windows.
If anybody has a cheat sheet on this process or info or experience and utility please let me know.
Just to be clear this has nothing to do with document encryption or PGP signatures although it is possible the different objectives might be combined but beyond my ken.
Budgie2.
Hi hendersj, many thanks. I have also posted on the LO forum and there is a great deal of reading required but most of the answers are there re digital signatures.
There is a post here from kariggest that suggests that I cannot use digital signature with an image from a signing but no matter.
There is an option in LO to export a document as a signed pdf which might be exactly what I am looking for on this occasion.
This too requires a CA Certificate and I believe the residual questions I have for this form concern the acquisition, storage and use of CA Certificate data and if I can make it work with KeePassXC.
Will read on.
Thanks again.
Budgie2
Perhaps I should start a new thread but Firefox is not accepting CACert.org connection.
I have read several threads from searches but all refer to ancient posts.
What on earth is going on if the website issuing certificates is not recognised?
Could it be my system has no loaded the required certificate?
I have done this for signing documents and saving off a PDF. The PDF itself is not digitally signed, but for the purposes I needed, it was good enough.
Hi and thanks for this. No idea why it is not made clearer by FF but I have it in my system from the repo. My problem is it is not being found by FF. I assume I have to import it but what and from where?
About digital signing. Of course, you can add one image from your signing. And you can make a digital sign in your document. But the image is not part of the digital sign. You have your certificate, and in your document you can select add digital sign and obtain your digital sign. Thats all.
You can do the same in your PDF i.e. with okular.
Maybe you wanted something like Autofirma (but this only works on PDF). You can digital sign your PDF and you can make view the digital sign and even you can add a image from your sign. Or even you can add a sing in your digital sing and another image (a logo, a image that you want).
About Firefox: make sure you have the trust checks in your certificate.
Hi nrickert,
I am continuing here as this is the main purpose of my original post.
I have ca-certificates-cacert in my system but I am needing more help on how to access and use this.
I am working on documents with LibreOffice writer or calc and the simple and most expedient way of signing these is to export as pdf and then add the security but when I look for the Digital Signature in the tab none are available from which to select.
That is where I am stuck.
To digitally sign a document you need to generate private/public key pair and use private key to sign a document. For a recipient to verify your document recipient must either have a copy of your public key obtained in such a way that the recipient is sure this public key belongs to you, or your public key has to be signed by someone the recipient trusts (which is what certificate is). One way to obtain such a key pair is to use one of trusted CA to request certificate.
This is not “digital signing”. This is “signing with a digital handwritten signature”, which is different - it’s inserting an image into the document, and has no cryptographic element at all.
“Digital signing” is, as others have explained, is entirely different, using digital keys to provide validation of a document’s authenticity. That has nothing to do with adding an image of your signature to the document.
If you want to prevent changes to the document, you can also password protect it. That’s not “digital signing” in the strictest sense, but it’s a means to prevent easy modification of the document (of course, passwords can be cracked).
If you need a way of handling legal documents, bear in mind that (1) nobody here is providing legal advice, and (2) you may want to look at using a solution that’s designed specifically for that, like Docusign or Adobe’s similar solution (Document Sign, I think it’s called). If someone is sending you a document for signature, you can usually ask that they send it using one of those tools so you can electronically sign it.
Yep, this is on a case to case basis. Digitally signed is quite complicated unless you use a third party like docusign.
Signature inserted using image in PDF can be edited by application like inkscape. Inkscape is a powerful application that can edit a true pdf file 100%…
If you need digital signing, your main problem is obtains something you can use as digital signing, of course. There’s a lot of ways to do that. In Plasma, you can use Kleopatra to make your certificate and this works fine. But when someone reads the document, he will have to trust that you are who are saying to be.
A lot of countries have implementate some type of certificates to do that, better or worst. I have one of that, so if I want to sign any document, I could do it: I can do it with PDF (with Okular) or even a odf (with LibreOffice).
But… LibreOffice uses the certificate store from your navigator, i.e. Firefox (or Thunderbird!). So you must use a certificate that works fine in the navigator.