Hi there,
My Idea:
It can be implemented by creating an encryption/decryption algorithm, in which encrypting a specific text message using predefined keys, and you get the encrypted text to the users as License Code.
Now, to verify the License Code, simply decrypt the License Code by the same predefined keys used to encrypt the text.
If the decrypted License Code equals to the text message then the License Code is correct.
I could implement it by using the RSA algorithm and by using C/C++. Take this example:
1. RSA Application generates 2 keys for the encryption and 2 keys for the decryption.
2. Use the 2 keys for the encryption process to encrypt a specific text message you select, for example "the moon is a very nice place to visit but not to live".
3. The encryption process will get you the encryption of the text in any format as text, binary or hex decimal, let us say we will use hex decimal "05373FB736A5184F766C0018373A85732FBDE".
4. Provide the "05373FB736A5184F766C0018373A85732FBDE" as License Code for all users for this month.
5. When the user tries to use the License Code, you verify it by sending the "05373FB736A5184F766C0018373A85732FBDE" code to the RSA App with pre-generated decryption keys.
The application checks if the decryption of "05373FB736A5184F766C0018373A85732FBDE" = "the moon is a very nice place to visit but not to live" then the license code is correct, and otherwise is not correct.
For more info. please contact me