I think by doing it this way you don't encourage your colleagues to steal your signature. The method below I think is the best way I found, and is Use the signature that appears in the document to protect it from being copied, printed or copied to another document, and protect it with an electronic signature. Note: The signature image in the final PDF file should match the digital signature on the original PDF document. It might be helpful to create multiple copies of your PDFs, just in case. Note: When you mark a PDF with a password for editing, you are not copying the content of the PDF, but the password. You could also use “Encrypt” the document, and use the password when you edit it. When I use the “Encrypt” option, the “Encrypt the Image” and “Encrypt the Signature” options, I make the following changes in Inkscape: 2 Answer 2 You can encrypt or decrypt files using a private key in Inkscape. Please read This is how to copy files to the SD Card for technical explanation and details. Inkscape for PDF You can also use the Inkscape to turn a PDF into a “signature”. This can be done in a few options, as shown in the following picture. It is a little trickier than it looks on the screen, but it's not hard and not all that hard, either. Basically, you need to copy an image, which in Inkscape is a layer, and paste it onto the “Sign-in/Signature” page of the PDF page, as shown in the following picture. Click on the “Sign-in” page, choose the “Fill Signature” option, then click on the image you copied, which is “Signature” for those of you who are familiar with Inkscape, and which appears in the bottom right-hand corner of the PDF. Click “Apply” and click on “Save Signature” button to save the signature. As this PDF is a “Signature” file, you might get an error that says “Signature is not a valid signature, please verify if you are the owner”. I believe they are saying that it cannot be verified, because it is encrypted with a digital key used for signing.