Code Signing certificates attach a digital signature to code to validate that the content has not been altered since it was signed and distributed. Code signing works with software components, macros, firmware images, configuration files, and other types of content.
Browsers and operating systems are continually improving security measures, and many currently scan downloaded files to check for code signatures.
For more information, see Microsoft®'s Introduction to Code Signing.
Driver Signing certificates (also know as kernel-mode Code Signing certificates) are identical to Code Signing certificates, except they are specifically designed to secure code from Windows® hardware drivers and operating systems. Driver Signing certificates are required to sign all drivers on any Windows Vista® operating system or later.
For more information, see Microsoft's Driver Signing article.