There are many ways to get and use digital signatures. They are easily transportable, cannot be imitated by someone else, and can be time-stamped. Digital signatures can be used with any kind of message or document, encrypted or not.
With all of my clients, we sign a contract that includes all facets of a project. Some clients, especially in the pharmaceutical industry, also require a non-disclosure agreement (NDA). I used to print out the contract or NDA, sign it, scan it and then email it back to the client.
Digital signatures have made this multistep process obsolete. Now I just open the contract or NDA in Adobe Acrobat Professional and using a digital signature, sign the document, save it and send it back as an attachment via email. So far, all my clients have accepted the digital signature.
Adobe Acrobat Professional allows me to scan a digital image of my signature, create a digital ID to sign documents or use encryption and public key infrastructure (PKI) support through the Adobe Approved Trust List (AATL). I usually digitally sign documents using a digital ID. The recipient of the PDF and signature can use the free Adobe Reader to validate digital signatures and verify document certification.
And the free Adobe Reader 10 allows anyone to add digital signatures. (Video tutorial: http://tv.adobe.com/watch/learn-acrobat-x/how-to-digitally-sign-a-document-with-adobe-reader/.)
For large organizations, third party digital signature software is worth the investment. There are many companies out there. Capterra’s directory of digital signature software tools lists 24 companies.
Do you sign your documents digitally? How do you do it and what software do you use?