A lock screen is a computer user interface element used by various operating systems. They regulate immediate access to a device by requiring the user to perform a certain action in order to receive access, such as entering a password, using a certain button combination, or performing a certain gesture using a device's touchscreen. There are various authentication methods to get past the lock screen, with the most popular and common ones being personal identification numbers (PINs), the Android pattern lock, and biometrics.

TouchWiz is a discontinued user interface developed by Samsung Electronics with partners, featuring a full touch user interface. It is sometimes incorrectly referred to as an operating system. TouchWiz was used internally by Samsung for smartphones, feature phones and tablet computers, and was not available for licensing by external parties. The Android version of TouchWiz also comes with the Samsung-made app store Samsung Galaxy Store. It was replaced by Samsung Experience in 2017 with the release of Android 7.1.1 “Nougat”*.