How many types of code signing certificates do I need?

In Canada, website SSL certificates can be had for as low as US$10. Unfortuna开发者_Python百科tely, code signing certificates cost about 10 time as much.

One website mentions Windows Vista compatibility... This seems strange, because my assumption is they must support Windows XP, Windows Vista, Windows 7, Windows Server 2003, and Windows Server 2008 or they would be useless.

From https://secure.ksoftware.net/code_signing.html US$99:

• Supported Platforms
  • Microsoft Authenticode. Sign any Microsoft executable format (32 and 64 bit EXE, DLL, OCX, DLL or any ActiveX control). Signing hardware drivers is not currently supported.
  • Abode AIR. Sign any Adobe AIR application.
  • Java. Sign any JAR applet
  • Microsoft Office. Sign any MS Office Macro or VBA (Visual Basic for Applications) file.
  • Mozilla. Sign any Mozilla Object file.

The implication is that a single code signing certificate can do ALL of the above.

K Software actually discounts Commodo certificates and the Commode website is unclear.

Will ONE code signing certificate be enough or do I need one for Microsoft executables, and a second for things like Word and Excel macros?

My main goal is to sign things like Visual Studio 2008 code snippets so that I can export them securely. However, I would like to be able to use the same code signing certificate for signing other items too.

a. One should be enough

b. The only reason to buy it rather than make it yourself is to avoid a warning when installing the code. Other than that, nobody really cares (and how many times did you see this working and pressed continue without even thinking about it?)