Digital signatures are being used increasingly to legally bind relying parties to their online transactions, to verify the identity of a person who signed document. Digital signatures provide security based in encryption technologies and help mitigate risk associated with electronic business transactions. Microsoft added digital signatures in Office 2010. Office 2010 digital signatures are able to use advanced algorithms (like elliptic curve public key algorithm) supported by Windows Vista and later. All supported operating systems also use of more robust hashing algorithms, like SHA-512. To create a digital signature, you must’ve a digital certificate, which proves your identity to relying parties, and should be obtained from a reputable certificate authority (CA). If you don’t have a digital certificate, Microsoft integrated partners as well as other advanced signature services into Office at Office Marketplace. “In Word, Excel and PowerPoint 2010, a digital signature can be added from Office Backstage View. A signature line or signature stamp can be added in Word, Excel, and InfoPath by going to Insert Tab.”

Signature line looks like this:

Signature stamp (more commonly used in Eastern Asia) looks like this: