Code signing is the process of applying a digital signature to software/applications. It's the virtual equivalent to shrink-wrapping CD based software for distribution. Code Signing informs a user who is downloading “signed” software that it is legitimate, it comes from a known software vendor, and that the code has not been tampered with since being published.
Why Should I Sign Code?
Customers who download software need to be assured of who published the software and whether the software has been tampered with or not. Code Signing provides this assurance and offers your users peace of mind when accessing your software online.
Digitally Signed Code
Unsigned applications display worrying security alerts to end users, warning them that the publisher of the application is unknown and advising them to only install applications from sources they trust.
Code Signed with a Code Signing Certificate
Digitally signed applications prominently display the name of the publisher on the install screen, alleviating the end user's concern over only downloading from trusted sources.