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Please Note: This article is written for users of the following Microsoft Excel versions: 2002 and 2003. If you are using a later version (Excel 2007 or later), this tip may not work for you. For a version of this tip written specifically for later versions of Excel, click here: Digital Signatures for Macros.
When you create macros and share them with others, the availability of those macros depends on the security settings on the user's machine. If the security level is set high enough, the user may not even be able to use the macros at all.
One way to help users utilize your macros is to digitally sign them. This capability was introduced by Microsoft in Excel 2002. A digital signature allows a user to know that a macro comes from a trusted source and that it hasn't been modified since it was originally saved by that trusted source. In other words, it is a way for users to be sure that a macro hasn't been tampered with. (Sort of like the product safety seals on some consumer foods and pharmaceuticals.)
In order to digitally sign a macro, you need to first obtain a digital certificate. A certificate is a "seal of approval" from a trusted third party that you are who you say you are. You can get digital certificates from a variety of commercial certificate authorities, each of which has different requirements of how you go about certifying your identity.
You can also create your own digital certificate for testing purposes using the program SelfCert.exe, which is provided with Microsoft Office 2002 and 2003. This route is great for testing, but it won't help you when you distribute your macros to others; you'll still need the certificate from the third-party authority. You can find more information about the SelfCert.exe program by using Excel's online help and searching for "selfcert."
Once you have a digital certificate, you can digitally sign your macro project in this manner:
You can find more information about digital signatures in Excel's Help system. You can also find some great information about both certificates and signatures at this page in the Knowledge Base if you are using Excel 2002:
If you are using Excel 2003, see this page instead:
ExcelTips is your source for cost-effective Microsoft Excel training. This tip (3107) applies to Microsoft Excel 2002 and 2003. You can find a version of this tip for the ribbon interface of Excel (Excel 2007 and later) here: Digital Signatures for Macros.
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