Use Biometric Authentication
Usernames and passwords combinations have been in use for decades, previous and ongoing security breaches at major businesses result in millions of username/password combinations being stolen on a regular basis. To make matters worse many people still use the same password to access multiple accounts so once stolen multiple accounts are compromised.
Biometric authentication is less vulnerable because a user's biometric data is unique making it very difficult for an attacker to fraudulently replicate an individual's eye, voice, fingerprint or facial recognition scan.
With modern mobile devices biometric authentication only takes a moment and apart from being more secure than passwords it's usually far more more convenient.
Common Biometric Authentication Methods include
Facial Recognition systems create an encrypted digital model using your facial data by analysing face geometry, for example the distances between your eyes, chin and nose, etc, and store it for reference. To authenticate your face is scanned in real time usually with your smartphone and compared to the reference.
Fingerprint Recognition systems create an encrypted digital model using ridges and patterns from your fingerprint and store it for reference. To authenticate your fingerprint is scanned in real time usually with your smartphone and compared to the reference.
Voice recognition systems analyse the sound of your voice and store it for reference. To authenticate your voice is recorded in real time usually with your smartphone and compared to the reference.
Eye Recognition systems analyse the coloured rings found in the iris (iris recognition) or the pattern of blood vessels in the eye (retina recognition) and map these patterns or colours. To authenticate your eye is scanned in real time and compared to the reference, with the retinal scan, a light shines into the eye to illuminate the blood vessels
With smartphones your biometric options work very well and are a fast and convenient method to verify your identity by using your personal physical characteristics but your device is only as secure as your weakest authentication method.
So if you use a simple pin number as an alternative authentication method this defeats the object of improving your security. Once you have Biometric Authentication in place you should set an extra-strong password as the alternative authentication method since you won't need to input it constantly