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mclarenceFlag for United States of America

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Locking down an Excel file ?

I have a MS excel file that is used to do some very complex and secertive calculation. I need to make it as secure as possible. I have password protected everything and made the sheets with the calculation tables "very hidden". Is there anything else i can do...? I was playing around with doing EFS file sharing but the issue with that is anyone who has access to the file also has to unencrypt the file and email outside the company. The idea is it should be accessible only from the internal network. It should never be email or access by more then the 10 people in the engineering group.
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mclarence
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Sorry that didnt sound right, It should say... Any who can access the file also has the ability to unencrypt and email it. I dont want people to have that capablity to be able to unencrypt it. This is encase someone tries to disclose properitery info with bad intent. They need to use the file and that is it.
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jack12387

I understand your problem, I think it is best to use VBAProject in the Excel file to lock more stuff down.  Furthermore, You can protect the viewing of the VBA codes itself by going into the VBA project properties.

Something nice to implement, (I haven't tried) VBAProject can possiblily enforcce NT authentication during first opening the Excel file.  I'm 90% certain this is possible.

Finally, I think your expectation need to be lowered abit.  Most software code can be reversed engineered/broken down, one way or another, if it is attained by someone determined to crack it.  You might want to fingerprinting excel file, then make sure this file does not get out of your company by web, email, ftp, ssh, etc.
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ECNSSMT

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and err... per the first part it lends enhancing capabilities to the native protection of what is offered in Excel....

Regards
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Tim Holman
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Thanks guys, a combination of water marks and IRM permissions gets me close enough to where i need to be!!!
Excellent....  Thanks for the points...