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1. Re: Once a PDF is digitally signed, how to I disable the "Clear signature" option? I cannot allow appli
Test Screen Name Jun 14, 2013 7:14 AM (in response to Izzoard)What's the problem? If the signature is removed so is the authenticity; it's as if it were saved unsigned (and hence unauthenticated)?
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2. Re: Once a PDF is digitally signed, how to I disable the "Clear signature" option? I cannot allow appli
Izzoard Jun 14, 2013 7:26 AM (in response to Test Screen Name)I work in an industry where once something is signed, it cannot become un-signed. If we wish to remove authentication of an approval, we have very strict rules.
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3. Re: Once a PDF is digitally signed, how to I disable the "Clear signature" option? I cannot allow appli
Test Screen Name Jun 14, 2013 7:56 AM (in response to Izzoard)The point is that this is trivial to achieve for anyone, even if the file is locked after signing.
They just need to keep a copy of the unsigned file, delete the signed one, and replace it with the unsigned file. So such protection means nothing.Repudiating signatures is a very bad thing, but it can only have real meaning if someone or some process knew about the signing. Otherwise, it's like someone signing a piece of paper, and destroying their signed copy without showing it to anyone; it's as if it never happened, and nothing was gained. If on the other hand a person has received the signed file, or a process has securely archived it, then removing a signature has no repudiating effect on the copy.
It can be hard to convert paper-based to electronic-based workflows where files can be freely duplicated, shared etc.
Clearly, though, if a person can sign a file, then others can act on that signature, and then the signer can still edit the original signed file, there is a big problem, not just of repudiation but of auditability.
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4. Re: Once a PDF is digitally signed, how to I disable the "Clear signature" option? I cannot allow appli
Izzoard Jun 17, 2013 2:04 AM (in response to Test Screen Name)Hi Screen name,
I'm aware of the surrounding issues and can only take appropriate control steps to prevent files being overwritten.
Still, my question remains:
Can I prevent the owner of a signature from clearing their signature once applied?
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5. Re: Once a PDF is digitally signed, how to I disable the "Clear signature" option? I cannot allow appli
isakten Jun 18, 2013 9:34 AM (in response to Izzoard)Acrobat XI shows in the signature panel deleted signatures. So, if you delete your own signature, there is now a record in the Acrobat/Reader UI and you superiors will call you on the carpet.



