by Allen Wyatt
(last updated November 7, 2015)
Dennis wonders if there is a way to lock a workbook in such a way that would prevent the "password breaker" VBA codes (or anything else for that matter) from cracking the password.
The short answer: sort of. I know that answer sounds rather wishy-washy, and perhaps non-committal, but there is a reason for that.
You see, the real answer depends on whether you want to rely strictly on what Microsoft has built into Excel or you want to rely on third parties. The tools that Microsoft provides for protecting workbooks aren't really that great. They've been getting better with each new version of Office, but they still aren't impossible to crack.
To get around this, many people don't distribute workbooks to others. Instead, they generate results in some other format—such as a PDF file—and then distribute those. This protects the original data in the worksheet and keeps the formulas in the worksheet away from others entirely.
If you need to distribute actual workbooks, the best approach is to not rely on Microsoft and, instead, look to third-party solutions. A good encryption tool could be used to encrypt the workbook file, making it all but impossible for anyone without the password to open it. Some even require two-pass authorization, which further protects whatever is in the file.
Understand, as well, that the type of third-party tools I'm talking about aren't limited to encrypting Excel workbooks. They are the type of tools that are more general-purpose in nature, providing the ability to encrypt any type of computer file.
How do you find good third-party encryption tools? You can do a search for "strong encryption," "encryption programs," or "encryption utilities" using your favorite browser, and it should turn up plenty of alternatives. When you find something that looks promising, make sure you then do a search using the product name and/or company name as the keyword. That will allow you to see if others are having problems with the product or with the company that makes the product.
Finally, you should understand that no matter what level of protection you use or what approach you use to protection, it is virtually impossible to "guarantee" that nobody can crack the encryption. Think NSA—there is a good bet that they (or other state-sponsored agencies) could, given enough time, crack your workbook. Fortunately, unless you are protecting state secrets or your workbook implements a way to select every winning lottery number there is, such folks won't spend the time or resources necessary to get at your data.
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