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Open Source Software protection system - Part 1

, 18 Apr 2004
Outlines in developing an open source implementation of a new software protection system.
encryptrelease_demo.zip
Encrypt.exe
hashlibproper.dll
SysInfo.dll
encrypt_src.zip
Encrypt.dsp
Encrypt.dsw
HashLibProper.dll
HashLibProper.lib
SysInfo.dll
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 Demo application to show the modus operandi (hope I got that right ;)
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Step 1: Copy any file of your choice to the folder containing Encrypt.EXE and RENAME it to OriginalData.dat

Step 2: Run Encrypt.EXE and depending upon your machine you will get a key which is the MD5 digest of your system info

Step 3: Press OK to encrypt the dat file 

[In practice, the customer/user will have the module which only creates teh MD5 digest of the system info string and send both to the developer, i.e he gets to execute Step 2
The developer/publisher on getting the key does Step 3 and sends the encryped file and other supporting program files back to the user.]

Step 4: Run Encrypt.EXE and now press Cancel to decrypt the encrypted data file.The decrypted data file will be named DecryptedData.dat

Step 5: Rename DecryptedData.dat to whatever the original filename was and it should be the same !

[The above two steps will be executed automatically by the Loader program on the user's computer.]

Step 6: Perform Steps 4 and 5 again BUT NOW on a different machine configuration (maybe rename a drive, reassign drive letter or run a different OS) and though DecryptedData.dat is created allright, since the key was not the same DecryptedData.dat it's just garbage !

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About the Author

Kamal Shankar
Web Developer
United States United States
Kamal Shankar is a programming freak (or so he feels).He currently lives in the Salt Lake City and loves doing what he has been since 1990 - coding horribly Wink | ;)

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