Excel Security
in [Programming]
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From: ShaunP. on 12 Apr 2010 12:08 Greetings I'm currently trying to develop a 'solution' to deliver to my clients. I'm almost definitely going to be using Excel barring any showstoppers - since this is what my clients know best. I'm trying to avoid using VSTO, and would like to be able to stick with Macros and VB code within Excel. My biggest concern is security. I absolutely need to be able to securely hide my formulas. The ease of use and familiarity of Excel is only worth 0.1% of the cost of the formulas. My clients don't need to know the formulas, or how they work, they only need to be able to use them. I've heard that Excel 2007 password protection is quite abit better than previous versions - is this true? I realise that nothing is ever 100% secure, but I need to be sure that the average computer user can't just google a password breaker and get to the formulas. What if my clients are running Excel 2003? Would a workbook built in 2007 retain its security if opened in 2003? Any advice is greatly appreciated. Thank you for your time and input.
From: JLGWhiz on 12 Apr 2010 12:24 You will be very lucky to find a really secure method to hide formulas using Excel and VBA. Formulas entered on the worksheet appear in the formula bar when the respective cell is selected and formulas used in VBA can only be protected from people who are deathly afraid of computers at the outset. Almost any knowledgeable user of Excel can get to the code in VBA. The best you can do is to password protect the code by going intp the VBE and View>VBA Project Properties>Protection and check the Lock Project for Viewing box, then put a password on it. "ShaunP." <ShaunP.(a)discussions.microsoft.com> wrote in message news:EE58BE78-2AF3-426E-9B51-3F213FC8DE42(a)microsoft.com... > Greetings > > I'm currently trying to develop a 'solution' to deliver to my clients. > I'm > almost definitely going to be using Excel barring any showstoppers - since > this is what my clients know best. I'm trying to avoid using VSTO, and > would > like to be able to stick with Macros and VB code within Excel. > > My biggest concern is security. I absolutely need to be able to securely > hide my formulas. The ease of use and familiarity of Excel is only worth > 0.1% of the cost of the formulas. My clients don't need to know the > formulas, > or how they work, they only need to be able to use them. > > I've heard that Excel 2007 password protection is quite abit better than > previous versions - is this true? I realise that nothing is ever 100% > secure, > but I need to be sure that the average computer user can't just google a > password breaker and get to the formulas. > > What if my clients are running Excel 2003? Would a workbook built in 2007 > retain its security if opened in 2003? > > Any advice is greatly appreciated. Thank you for your time and input.
From: ShaunP. on 12 Apr 2010 12:47 Sorry, I should have mentioned that I have looked into some software out there like DoneEx's XCell Compiler and ExcelLock. I'm just wary of how secure these might actually be aswell. If anyone has any suggestions on 3rd party apps like these, I'd be willing to explore those options aswell.
From: ShaunP. on 12 Apr 2010 15:28 This is a little dissapointing to hear. How is it that Microsoft hasn't taken the time to implement this? Being the the biggest mainstream spreadsheet application without any reliable security? Countless businesses are at risk of compromise with just a few google searches? There must be someway more reliable and secure.
From: Martin Brown on 12 Apr 2010 17:29
ShaunP. wrote: > This is a little dissapointing to hear. > > How is it that Microsoft hasn't taken the time to implement this? Being the > the biggest mainstream spreadsheet application without any reliable security? > Countless businesses are at risk of compromise with just a few google > searches? > > There must be someway more reliable and secure. If you are that concerned about protecting intellectual property then you probably will have to put the critical calculations in a compiled encrypted external DLL. Even then it can still be disassembled by a sufficiently determined adversary. You might want to experiment with some of the available password crackers to see how easily they can break into protected VBA code. My instinct is that for a suitably awkward choice of long password that isn't in any dictionary and uses the full range of characters the Excel security isn't brilliant but it will discourage most people. My recollection is that they can break into worksheets very quickly, but that VBA puts up a bit of resistance. YMMV Somebody described a fairly devious way to trick XL into not displayiong the project code window in a thread fairly recently. I haven't tried it. Given how bad Excel 2007 is in other areas like graphics its security is better than you might expect. Regards, Martin Brown |