16.4. Digital Signatures
You have probably seen digital signature dialog boxes in the various Microsoft Office applications, as well as other applications you have created.
Digital signatures enable developers to create a public/private key pair set to use for authentication purposes. This is much like a driver's license: You show it to the police officer when you are pulled over, he goes to his car and runs it, and the computer tells him that yes you are in fact so and so and that your record is clear. In the same way, a digital signature is a way for software to verify the identity of the creator or publisher of the form, application, and so on.
16.4.1. Using Digital Signatures with InfoPath
InfoPath enables you to sign your forms with a digital signature to assure others that the form did in fact did come from you or your company.
16.4.1.1. Try It Out: Creating a Test Digital for Testing
To create a test signature used on the local machine, you must follow a few simple steps.
Download and install the Authenticode for Internet Explorer from:
http://www.microsoft.com/downloads/details.aspx?FamilyID=2B742795-D0F0-4A66-B27F-22A95FCD3425&displaylang=en
Open up the command-line utility and navigate to the C:inetsdkin directory, or wherever the makecert.exe utility is located.
Type in the following to create your certificate; take note that you can replace the string "CN:TestCertificate" with "CN:" and whatever name you want to use for the signiture, that would have more meaning for you, and not imply that it was a test certificate.
makecert -n "CN:TestCertificate" -cy end -a sha1 -sky Signature -m 1 -iv certRoot.pvk -ic certRoot.cer -ss MY
This will add the TestCertificate into the users Personal store.
Now the new digital signature can be used to sign forms. You get a chance to use it in the following Try It Out.
16.4.1.2. Try It Out: Sign the Form with the Digital Signature
Using the form Chapter 16.xsn in Design view:
Select from the Tools
Digital Signatures. You will be prompted with the dialog box in Figure 16-8. This dialog box will enable you to view and Add/Remove Digital Signatures from your form.Figure 16.8. Figure 16-8
Click the Add... button. The Digital Signature Wizard appears and walks you through some simple steps in getting your form signed. You can see this page in Figure 16-9.
Figure 16.9. Figure 16-9
Click Next. On this page, you will see the Test Certificate created in the previous Try It Out, as displayed in Figure 16-10.
Figure 16.10. Figure 16-10
Click the Next button, choosing the test certificate. The next page of the Digital Signature Wizard is shown in Figure 16-11 and lets you specify some comments and summarize the digital signature.
Figure 16.11. Figure 16-11
Click Finish. The last page of the Digital Signature Wizard prompts you to review and verify all your information as well as the information regarding your digital signature, as shown in Figure 16-12.
Check the box labeled I have verified this content before signing.
Click the Sign button.
You have now digitally signed your InfoPath form, and it is ready to be used.
Figure 16.12. Figure 16-12
