I've been asked to implement digital signatures for documents at work. I really need to read up more on the matter but several searches didn't make an obvious approach stand out.

Main features I would like to see represented in a solution are:

  • Insert a scanned image of the user's real paper-and-ink signature into an Office document such as Word, PDF, to make it look as if the user really signed the document when the document is printed.
  • The signature should guarantee that the document hasn't been tampered with.
  • The signature should uniquely match up with one person.
  • Have some sort of verification process so that the user's digital signature can be checked against an authority that guarantees that the chain of trust is indeed going back to the company.
  • Have a publicly accessible place where the validity of the user signatures issued for the company can be verified.

Surely we're not the first company that wants something like this..

Where would I go to find a body that understands what I'm trying to describe and can help me offer some guidance?

If this question is still to broad, please help me narrow it down further as I'm keen to get a dialog going that could be of use to the SE community as well.

  • How about getting in a consultant ;)? This question is probably going to be too broad and thus most likely be closed. – Lucas Kauffman Jun 24 '14 at 10:55
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    What is wrong with cryptographic digital signatures? Or are you just not familiar with the concept. Signing algorithms such as RSA, DSA, etc do all of this very well (with the exception of the ink signature image). No reason to create a new square wheel... – AviD Jun 24 '14 at 11:21
  • Digital signatures is exactly what we want but we need the ink-like graphical signature as well and it needs to integrate seamlessly with Office documents too. – captcha Jun 24 '14 at 22:01
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    There are digital signature products on the market that do all of this, even integrate with Office. Copy/Print/Document equipment vendors (Xerox, Ricoh, HP, etc.) often have a solution. – schroeder Jun 24 '14 at 22:19