"Forward locking" a workbook by limiting authorized use to a certain PC name

I've been trying to figure out a way to send a workbook to a customer but preventing them from forwarding it to others. I've investigated several options in this forum:
1) password protection - easily hacked and customer can always email someone the password in addition to the file
2) Restricting Permission by People via Windows Live ID - difficult to do with Office 2013 and my IT sysadmin says that this will only work internally in my company

But here's an idea that I'd love some feedback about:

When opening the workbook, is there any way for VBA to check the user's PC name against a list of authorized PC names embedded in the code and if the check fails then close the workbook?

Thanks!
Dave

its possible however if the end user hasn't enabled macro's etc. it wouldn't be triggered in the first instance. You could set some code to "very hide" every sheet apart from a holding sheet advising the user to enable the content, when closing so that if macros are disabled that's all they see.

however to answer your question directly; put this in a module

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and put this in the workbook_open event
call Check_Host

Thanks!!

This looks promising, but I changed EXAMPLE_COMPUTER_NAME to my computer name as I found it in Settings > PC Info in Windows 8 and it auto-closes the workbook when i open it regardless of whether i use ".Close False" or ".Close True". Were you able to get this working on your PC?

True or False just tells excel to save the workbook (true = save false = don't save) before close.

in a different workbook try using

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this should print what excel beleives your pc name to be just copy and paste into the code above. perhaps there's a "hidden" space in thier somehwere.

Thanks Kramxel.

Sorry to be dense but I put your Sub Check_Host code into the Workbook_Open event of ThisWorkbook. But i'm confused because you said I should put it into a module but I can't select a Workbook_Open event from Module1. And I'm not sure what you mean by call Check_Host.

Sorry, but I'm a bit of a novice just trying to do my best...

Ah, I figured it out. Thanks! This is a thing of beauty.

What about also putting in a "kill pill" expiration date by checking system date against a date in the code. if it's system date <= kill pill date then do nothing. if it's past the kill pill date then activeworkbook.close

Any idea how I would do something like this in addition to your computername method?

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I've added simple msgboxes so that you can see some of the details but by all means delete/comment these out for other code you might want to run.