A digital signature is a method to ensure the reliability of an electronic document. It also ensures that it was created and signed by known person and not altered after applying the digital signature to the document during the transition. Digital signatures provide security standards in encryption technologies and help to mitigate risk associated with electronic business transactions. With improvements to digital signing methods, MS Office aims to meet the information security needs of worldwide entities.
To create a digital signature, you must have a digital certificate, to prove your identity and it should be obtained from a reputable certificate authority (CA). If you do not have a digital certificate, Microsoft has the partners who provide digital certificates as well as other advanced signature services that are integrated into MS Office at the Office Marketplace.
Digital signatures help establish the following authentication measures:
• Authenticity: The digital signature helps to ensure that the signature is done by whom. This helps to prevent others from pretending to be the originator of a particular document.
• Integrity: The digital signature helps to ensure that the content has not been changed or tampered after applying the digital signature. This helps prevent documents from being intercepted and changed without knowledge of the originator of the document during the transition.
• Non-repudiation: The digital signature helps prove the origin of the signed content. "Repudiation" refers to the act of a signer's denial to any association with the signed content. This proves that the originator of the document is genuine, regardless of the claims of the signer. A signer cannot repudiate the signature on that document without repudiating his or her digital key as the other documents signed with that key.
Now let's come to the procedures for adding digital signatures to Microsoft Word 2010, 2007 or 2003 doc files:
Open MS Word 2010 document that you want to sign digitally.
Go to File > Info > Protect Documents.
Then choose Add a Digital Signature from the drop-down.
Click OK as shown in the following dialogue box.
Go to Insert tab and see the Signature Line is added to the menu. It includes Microsoft Office Signature Line, Stamp Signature Line, Add Signature Service.
Click on MS Signature Line and go to Signature Setup dialog box. Type the contents into the given fields and click OK.
Now this signature will appear in the Word document.
Double click on the Signature. Another dialog box pops up and click OK as shown in figure to continue.
Type your name or select image by clicking Select Image as your signature. Click Sign to finish.
Now you have finished adding digital signatures in Microsoft Office 2010.
You can also refer to this video demonstration
To add a digital signature, click on the Office Button on the top left corner of MS Word and select Prepare. In the menu, select Add a Digital Signature option.
Once the option is selected, you get a warning and here you can either get digital signature from third party or use the default one from Microsoft. The default one does not provide any warranty as it has legal enforceability in different countries.
Click on OK to select the default signature. If the document is not saved, then it prompts to save the document. Type the Purpose of signing this document in the space provided.
Click Sign button and the signature will be created. You can view the digital signature from the following menu: Prepare > View Digital Signatures). This will be available as a sidebar.
If you edit the document, then the signature will be invalid.
Open the document to be signed in Microsoft Office Word 2003.
Click Tools tab and select Options.
Click Security tab and select Digital Signatures.
Click Add and highlight the signature.
Click Yes to save the document before signing.
Click Yes to install the signature in the document.