What's the basic principle of iris scanning?

The iris recognition feature uses the unique characteristics of your irises, such as their shape and pattern, to strengthen the security of your device.
 
Your iris data can be used for various authentication purposes. After registering your irises, you can set the device to use your irises for the following features such as Screen lock, Web sign-in, Verify Samsung account, Secure Folder,
 
Samsung Pay (This feature may not be available depending on the region or service provider.)

• If you use your iris as a screen lock method, your irises cannot be used to unlock the screen when turning on the device. To use the device, you must unlock the screen using a pattern, PIN, or password you set when registering the irises. Be careful not to forget your pattern, PIN, or password.
 
• If your irises are not recognized, unlock the device using the pattern, PIN, or password you set when registering the irises, and then re-register your irises. If your pattern, PIN, or password is forgotten, you will not be able to use the device if you do not reset it. Samsung is not responsible for any data loss or inconvenience caused by forgotten unlock codes.