how to protect shareware?

I'm using a software protection product, SoftLocx, from BitArts.   I'm using the SoftLocx OCX to customize my licensing and wrapping my EXE with another feature of the product for disassembly deterrence.  If I were you, I'd use a commercial wrapper product for both licensing (demo -> purchase) and disassembly deterrence.

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The best recommendation I can make about shareware protection is to limit the features or functionality of your code when it is in demo mode.

The software I've found to be the best protected is as such.

Have your application on startup run an algorithm to determine a machine specific password. Use something like MB or CPU serial numbers, which can be pulled in code. Have your application email you this information, so that at your end you can determine what "password" your application has determined for itself. You can then give user this code on payment.

Like most others have already said, just write the app. with demo priviledges without the code.

Software protections schemes are easier to crack than they are to write... and those warez crackers have IQ's that are way above room temp so you better be really sharp or they will have your app on the warez groups the day after you distribute it.

-Never distribute a full version of your shareware on the web....
-Never depend on an activation code to unlock your demo for full functionallity...warez puppies love to write key-generator programs.
-If at all possible have your app check a list of authorized users on the web each time before it runs.
This gives you a server log entry that shows the users IP address... if the same registered app starts getting logged from many differing IP's then you can remove it's authorizing data from the web and it will no longer function ;-)
-Embed personal info about the user into the app... having it self modify at the direction of the end user is best..it makes them nervous about passing the program around.
-Have the program modify itself as it runs... this makes crackers very nervous... they will drive themselves crazy trying to figure out what is going on... crackers are always looking for differences between a registered app and an unregistered copy...or between 2 different registered copies...this gives them valuable clues about your protection methods.... but if your exe is ever changing it will be maddening ;-)
-Use a LOT of different areas of the exe to store protection data in... and make the data alter before each execution.... call different check routines randomly... this makes sure that eventually one of the routines will hit and catch the unauthorized user.
-Make liberal use of encryption... the simple RC4 stream cypher will do wonders....
-Use various machine identifiers in your protection code...motherboard id, user names,hd serial, bios type..os type..etc

Maybe the best protection is to make a good program and sell it at a very reasonable price and have all the documentation only in written form.... warez types hate to scan in documents... it's not as much fun as looking over your exe with a hex-editor :-)

Put a statement in your about box or help file that says that your program can defeat a firewall and send data to you over the net that will identify them as an unauthorized user....this will scare off many bootleggers.
many will scoff and say it's hogwash.... but actually there is a very simple way to have a delphi app send data through a firewall... takes only a few lines of code and I tested it against BlackIce,ZoneAlarm and Norton... and it works fine... you can send data both in and out.....the method is so basic and simple that when you tell someone how to do it they say "Why didn't I think of that!" ..so just think about it awhile and it will come to you how to do it.... but I'm not sure about the legality of using it...of course if you warn the user that the program can do this then one would think.........?

If you need info about making self-modifying delphi exe's then email me and I will send you a useful unit I wrote...