Helping people with computers... one answer at a time.
I won't tell you how to crack an Excel password, but I will tell you a better way to keep it protected.
How to remove password protection in Excel worksheet? I've forgotten my Excel worksheet password. How do I recover this?
In this excerpt from Answercast #25, I look at the way applications provide security for data and suggest a better way to keep your valuable information safe.
Unfortunately, these are the types of questions that I don't answer directly. You may very well be totally honest with me. You may very well be totally the person who owns this spreadsheet, who legitimately forgot a password.
On the other hand, you might very well be the person who stole this spreadsheet and is trying to crack into it. So having said that, I don't have a specific answer for you. This isn't a tool set that I have recommendations for, or that I have a lot of interest in providing recommendations for: just because it can be abused so easily.
That being said, I would suggest that you go ahead and look in Google. If you Google for something like "Excel spreadsheet crack" or "Excel password crack," you will probably find numerous utilities that will attempt to do the job for you. Most of it, I believe is done, by brute force, but there are some other techniques as well.
The real reason I'm taking this question and answering it is not so much to provide you an answer (for which I apologize), but to show most other people just how insecure most kinds of application embedded encryption really is. I don't really want to slam the Excel people too hard, because in fact, what they have is better, much better than it used to be. But it is still fundamentally crackable to someone who has sufficient resources and sufficient motivation.
In reality, the right way to keep a document (like an Excel spreadsheet, or a Word document, or an Open Office document, or pretty much any document that you happen to have) safe from prying eyes is not to use the application itself to encrypt the data. Rather, encrypt it using a third-party program.
AxCrypt is a good utility for standalone files.
TrueCrypt is a great way to encrypt collections of documents.
This is usually more robust than the encryption and protection that is included in applications themselves.
They're like padlocks: I look at application passwords and application encryption as padlocks.
They're really, really good at keeping honest people honest. They will put up a barrier that will prevent honest people from attempting to open the document.
However, it's the dishonest people that you really want to worry
about... and for those kinds of folks, you probably want to use a more robust, a
more dedicated tool that is focused specifically on encryption and security:
like as I said, AxCrypt or
Next from Answercast #25 – I forgot my BIOS password, how do I get into my machine?