If you mean a true digital signature, rather than a scanned scribble, it is not only not done but absolutely impossible.
What it would mean was that software could take a signed document, and make a new signed document with the same signature. Though this would be very useful, it would also mean that people could take any document and use the signature to sign something else (a mortgage on your house perhaps...)
In the same way, once a PDF is signed, any change leaves the signature invalid. Signing has to be the very last thing.
For documentary proof, you can put attachments in a PDF, and this could include a signed Word document, which could be extracted for checking.
Ok, Thank you a lot, Test Screen Name !
Yes, I was actually considering the case of a really digital signature (not only a scribble), of course.
So I understand that the digital signature is not conserved as such trough this conversion.
I am french speaking, and I took a moment to understand you second paragraph... which seems to be obvious enought, indeed:
Yes it would be useful to recognize the signature form a Word converted to a Pdf, but it could mean that, if the signature is identified as such - I was no thinking about to get back the signature separately -, a simple conversion of a .docx in .pdf would be an alteration of data integrity (so, not anymore data intergrity could be garanted).
It was clear for me that a signature meant more or less explicitely, that the file could not be modified. But I was very innocent to consider a file only for its "visible characters", rather than the file format, which is also a part of data integrity - of course...
Allright, your answered perfectly to my question, I'll vote for you, as helpful, and correct.
Tank you one more time !
A digital signature contains a hash of the bytes of the signed document. The bytes of a Word document are very different from the bytes in a PDF document that displays the same content. Hence the digital signature on a PDF document must be very different from the digital signature on the Word document, which means that you must resign. If you have a visual representation of the digital signature in the Word document, the Word-to-PDF converter may preserve its image in the PDF document but this is not the same as a real digital signature.