A free app for Android, by F. Zander.

I know getting in touch with your feelings and emotions is a must to have a healthy mental health. Writing your emotions and everything you like in a diary is a good way of expressing what you feel and will prevent you from bottling or suppressing what you really feel inside. This application called Diary app with lock keeps everything you write because it has a security prompt like fingerprint authentication to keep your secured and protected. Lastly, you don’t have to worry about anything else because this application is totally free. This does not require you to pay for any monthly subscriptions. You can share this with your close friends and family.