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Excel Security
Hello i have written a program that defines and works out very lengthy formulas. I am trying to sell the program for what i believe to be enough money to protect. what i need is to be able to burn it on to a cd the put a time limit on the cd hence the user cannot use it after say 30 days or 5 uses. this would not be drama if i could save the file. e.g just use a counter that is VBA protected. But because it is on a cd it cannot save. i tried an idea of using the current time and date to be checked when excel started and that gave me a protection in which i was satisfied with. however once the 30 days up cd is unusable i could put a password on it to override the time checker however my buyer would have to enter the password every time for use. So basically what i need/want is a program excel/not excel that will limit the usage on the cd and that is full changeable and overidden i was thinking that once the workbook was purchased that the password i give them would then delete a line of code enabling them to save the workbook as it is save protected ? can anyone help ? -- Zygan ------------------------------------------------------------------------ Zygan's Profile: http://www.excelforum.com/member.php...o&userid=34423 View this thread: http://www.excelforum.com/showthread...hreadid=547081 |
Excel Security
Any security device you come up with can be easily defeated but you could
write a entry to the registry when the password is first entered and then check for it before presenting the password dialog again. -- Jim "Zygan" wrote in message ... | | Hello i have written a program that defines and works out very lengthy | formulas. I am trying to sell the program for what i believe to be | enough money to protect. what i need is to be able to burn it on to a | cd the put a time limit on the cd hence the user cannot use it after | say 30 days or 5 uses. this would not be drama if i could save the | file. e.g just use a counter that is VBA protected. But because it is | on a cd it cannot save. i tried an idea of using the current time and | date to be checked when excel started and that gave me a protection in | which i was satisfied with. however once the 30 days up cd is unusable | i could put a password on it to override the time checker however my | buyer would have to enter the password every time for use. So basically | what i need/want is a program excel/not excel that will limit the usage | on the cd and that is full changeable and overidden i was thinking that | once the workbook was purchased that the password i give them would then | delete a line of code enabling them to save the workbook as it is save | protected ? can anyone help ? | | | -- | Zygan | ------------------------------------------------------------------------ | Zygan's Profile: http://www.excelforum.com/member.php...o&userid=34423 | View this thread: http://www.excelforum.com/showthread...hreadid=547081 | |
Excel Security
The other folks put it mildly. You cannot create an Excel-based application that you can sell and protect from duplication and
elimination of all security and almost all of the profits you seek. You may in fact find your new app everywhere on the internet with users laughing at your attempt to hide it. If you want more advice on this, you might write to John Walkenbach (j-walk.com) and ask him how he avoids getting ripped off with his Excel add-in. He may tell you that his program is cheap enough and his reputation is solid enough that people generally don't want to rip him off and also don't feel the cost of a hacking program is worth the savings. The PUP add-in he sells is an Excel tool, not a stand-alone program. He allows a free trial version and after that I think he uses nag pop-ups to register rather than a self-destruct routine. I'm sure he will offer good advice, but in the end, you can't lock down an Excel-based app....yet. The new Excel due out in a few months might offer much stronger security than the old one. That would give you more of a fighting chance. In any case, prepare to not charge much for your application or it will get hacked and used for free, that is your no money back guarantee. There are so many people out there who spend all their time working on hacking programs that you just can't stay ahead of them; just ask Microsoft. -- RMC,CPA "Zygan" wrote in message ... Hello i have written a program that defines and works out very lengthy formulas. I am trying to sell the program for what i believe to be enough money to protect. what i need is to be able to burn it on to a cd the put a time limit on the cd hence the user cannot use it after say 30 days or 5 uses. this would not be drama if i could save the file. e.g just use a counter that is VBA protected. But because it is on a cd it cannot save. i tried an idea of using the current time and date to be checked when excel started and that gave me a protection in which i was satisfied with. however once the 30 days up cd is unusable i could put a password on it to override the time checker however my buyer would have to enter the password every time for use. So basically what i need/want is a program excel/not excel that will limit the usage on the cd and that is full changeable and overidden i was thinking that once the workbook was purchased that the password i give them would then delete a line of code enabling them to save the workbook as it is save protected ? can anyone help ? -- Zygan ------------------------------------------------------------------------ Zygan's Profile: http://www.excelforum.com/member.php...o&userid=34423 View this thread: http://www.excelforum.com/showthread...hreadid=547081 |
Excel Security
thanks for the advice i dont really care if someone hacks it because its such a large program that i would only give it to potential buyers and the program is copyright to me. Plus to access a trial they have to sign an agreement written by my solictor to not distrubute the software or reproduce. However my solictor says that i cannot put a time limit on the agreement with my potential buyer as my program does not have a time limit therefore once they sign to a trial its there for ever as a trial. However me solictor says that if the program informs them of "trial" period and they hack it they have breached copyright laws. So forgive my rudeness but the question i pose is. hackable or not (nothing is ever safe) I need a time limit or a non-excel program to put a time limit on the workbook even if it is not 100% proof. It just simply needs to work. I will check out John Walkenbach thanks for the advice. -- Zygan ------------------------------------------------------------------------ Zygan's Profile: http://www.excelforum.com/member.php...o&userid=34423 View this thread: http://www.excelforum.com/showthread...hreadid=547081 |
Excel Security
John can probably help at least to a limited extent. It does involve laws in different countries but he should still have something
worthwhile to say. Also, We tend to sometimes over-emphasize the lack of Excel security in newsgroups because so many people believe Excel has decent security when it doesn't have good security at all. Additionally, once the cat is out of the bag it is very, very hard to prove how it got out or that somebody did it with malicious intent. Good luck with your project. -- RMC,CPA "Zygan" wrote in message ... thanks for the advice i dont really care if someone hacks it because its such a large program that i would only give it to potential buyers and the program is copyright to me. Plus to access a trial they have to sign an agreement written by my solictor to not distrubute the software or reproduce. However my solictor says that i cannot put a time limit on the agreement with my potential buyer as my program does not have a time limit therefore once they sign to a trial its there for ever as a trial. However me solictor says that if the program informs them of "trial" period and they hack it they have breached copyright laws. So forgive my rudeness but the question i pose is. hackable or not (nothing is ever safe) I need a time limit or a non-excel program to put a time limit on the workbook even if it is not 100% proof. It just simply needs to work. I will check out John Walkenbach thanks for the advice. -- Zygan ------------------------------------------------------------------------ Zygan's Profile: http://www.excelforum.com/member.php...o&userid=34423 View this thread: http://www.excelforum.com/showthread...hreadid=547081 |
Excel Security
Have you considered just a Workbook_Open macro that would compare the current
date to a key date and if enabled, would erase all the good-stuff? Vaya con Dios, Chuck, CABGx3 "Zygan" wrote: Hello i have written a program that defines and works out very lengthy formulas. I am trying to sell the program for what i believe to be enough money to protect. what i need is to be able to burn it on to a cd the put a time limit on the cd hence the user cannot use it after say 30 days or 5 uses. this would not be drama if i could save the file. e.g just use a counter that is VBA protected. But because it is on a cd it cannot save. i tried an idea of using the current time and date to be checked when excel started and that gave me a protection in which i was satisfied with. however once the 30 days up cd is unusable i could put a password on it to override the time checker however my buyer would have to enter the password every time for use. So basically what i need/want is a program excel/not excel that will limit the usage on the cd and that is full changeable and overidden i was thinking that once the workbook was purchased that the password i give them would then delete a line of code enabling them to save the workbook as it is save protected ? can anyone help ? -- Zygan ------------------------------------------------------------------------ Zygan's Profile: http://www.excelforum.com/member.php...o&userid=34423 View this thread: http://www.excelforum.com/showthread...hreadid=547081 |
Excel Security
thanks for the advice -- Zygan ------------------------------------------------------------------------ Zygan's Profile: http://www.excelforum.com/member.php...o&userid=34423 View this thread: http://www.excelforum.com/showthread...hreadid=547081 |
Excel Security
Have you considered attaching a hardware lock? -- joseantonio ------------------------------------------------------------------------ joseantonio's Profile: http://www.excelforum.com/member.php...o&userid=35276 View this thread: http://www.excelforum.com/showthread...hreadid=547081 |
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