What are the six Ways to Lock Samsung Galaxy S9 and S9 Plus

The shape and patterns of your irises are unique to you. Using these distinct characteristics of your eyes to lock your device gives you an airtight security for your device.
Your iris data can also be used for various authentication purposes, for features such as Samsung Pass (Samsung account verification and web sign-in), Secure Folder and Samsung Pay (depending on the region and service provider). The iris sensor has been hidden in a hole on the upper bezel of your phone. 

Note: Galaxy S9 can register the irises of one person only. Additionally, if you use your irises as a screen lock method, you can't use them to unlock the screen when turning on the device. Instead, use your registered pattern, PIN or password to unlock the screen.

• To use it, hold up your phone and align your eyes with the twin circles on the screen to scan your irises.
• The iris sensor may not recognise you if you're wearing prescription glasses, sunglasses, colour contact lenses or circular contact lenses. Make sure to always remember your registered pattern, PIN or password. You need them to re-register your irises in case they will not be recognized. Without them, you will be forced to reset your phone. Note: Galaxy S9 can register the irises of one person only. Additionally, if you use your irises as a screen lock method, you can't use them to unlock the screen when turning on the device. Instead, use your registered pattern, PIN or password to unlock the screen.

Face recognition is one cool way to unlock the screen of your Galaxy S9. It's a fast and effortless method.
To use face recognition, just raise your phone as if you're taking a selfie. Make sure the camera lens is clean and you're in a well-lit area when using it. Face recognition is less secure than other screen lock methods such as iris scan, pattern, PIN and password. Your phone can be unlocked by someone who looks similar to you, such as a twin.

Note: Glasses, hats, makeup, beards and masks can affect the recognition process.

Galaxy S9's fingerprint sensor has moved beneath the rear camera, a more convenient spot that you can reach more easily and comfortably. Like your iris data, you can also use your fingerprint credentials to verify your identity on Samsung Pass, Secure Folder and Samsung Pay. You can register up to four fingerprints, in case you want to use multiple fingers for logging in.

Pattern Lock allows you to create a pattern to draw on the screen to unlock your device.

Passwords may be one of the oldest methods to secure a device's screen; it's guaranteed one of the safest. Create a password with a minimum of four digits but no more than 16 digits. For maximum security, choose a combination of letters and numbers.

Personal identification number or PIN is another secure method to lock a device. Your phone's PIN should be at least four digits.