A digital signature is essentially a message that is attached to an e-mail before sending, to help prove that the e-mail comes from who it appears to come from and that it was not altered during transmission. The easiest way to explain a digital signature is to list the steps involved in creating a digital signature and the reasons why you would want to create one. Here's our scenario:
Brian has just finished a chapter for the Outlook book and wants to send it to Tom.
However, Brian wants to make sure that when Tom gets the chapter, Tom knows that it has come from Brian and that the chapter has not been intercepted and altered by the evil author, John.
These steps are performed ...