Dear book owner, thank you for having the book.
As you maybe noticed inside the book, I am offering files to all the book owners.

This summer I hope to learn how to make passwords and use this to veriry if you have the book or not.
Until I know how this works, I have to find another solution.

This is my (temporary) solution:
Please send an email to me and tell me what file you want and what the second word is on page 23.

I will send you the requested file(s).