if i buy the license and enter the activation code in the program, anybody can decompile the exe and read the license key. even if the code gets obfuscated, strings dont get obfuscated. how can i prevent that out of 1000 users one steals my registration code and uses the chilkat library with my license without my knowledge?
You could store it encrypted in a table or ini file, and process it at runtime.
I use the chilkat RSA module.
But you would have to have the RSA key in your program to unlock that component.
Another way is to define a string, and store the key backward, with every third character being the key.
key is IBM_FG,
make key 1 letter off JCN_GH