Authenticode is Microsoft's technique of assuring the authenticitiy of data, and provide accountability for the data.
For example, lets say that you download a program from the Internet and it contains a Trojan Horse. Authenticode helps you in two ways:
- First, it provides authenticity. This verifies that nobody else has changed the data since it was created. For example, if you download pirated software from a website, check its signature. If it isn't valid, then there is a good chance that a hacker has added a Trojan Horse or a virus to the program.
- Second, it provides accountability. Lets say that you download software from a vendor, but it does something bad to your system. When you go back to the vendor, they could claim that it wasn't their fault. However, if the program was originally signed, the vendor cannot weasle out of its responsibilities.
There are two parts of an authenticode signature:
- A signature from the producer of the file. For example, Network ICE signs all its programs with its own signature. When downloading software that you think is from Network ICE, please check the signature first.
- A verification that the signature is who they claim they are. Anybody could claim to be Network ICE and sign a file. Network ICE has been verified by Verisign, who themselves have been verified by Microsoft and Netscape in their browsers.