HostUS's Two-Factor Authentication system is based on TOTP (Time Based Tokens), which will work with any TOTP / OAUTH software such as Google Authenticator for iOS or Android.
To enable, login to your HostUS account,
- Click the Hello, (name)! dropdown link
- Click Security Settings
- Under Two-Factor Authentication, click to enable
- Follow on-screen prompts and scan the QR code
- Log out then log in again