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.
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.
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:
Open up the command-line utility and navigate to the C:\inetsdk\bin 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 ...