You can set a passcode for each of your cameras through the YI Home Camera app. Every time you enter the video page, you will be required to input the correct PIN. You can set a pin following these steps:
Open the app, and enter the individual camera’s video page.
Press the settings icon in the upper right corner.
Under Security, enable “Pin Protection”.
Set up 4 digit password.
After configuring, you will enter the 4 digit password to access to the camera.
Also, every time somebody logs into your account, you will get a notification saying somebody is trying to login to your account.