I have written a windows app that is like an enigma machine, it's called Crypto Messenger & Crypto Notepad & file encryptor.
You can send and receive encrypted messages for people by clicking the 'encrypt' button and then the 'copy to clipboard' button and then pasting the encrypted text into your messaging app.
you can use it to write notes that you can store on your computer in encrypted form so no one can read it without knowing the password and having this app.
It can also...