Secure Element (SE) is a tamper-proof microprocessor chip. It stores sensitive data and runs secure, trusted apps. SE has its own OS. This helps it keep the data and applications safe from other applications running on the same device. SE is used in smartphones, tablets, wearables and other Internet of Things devices. It can be embedded or integrated into the device, but a SIM card or a smart microSD can also act as an SE.
A Secure Element stores private keys, PIN codes, eID documents, signatures, payment information and other identification and authentication data. For example, when using an iPhone to pay at a store, you first have to authenticate yourself to the SE using Touch ID, PIN or Face ID. Then the SE sends the data needed to the POS terminal via NFC.
In the automotive industry, SE is used to store digital car keys. For unlocking the doors, an application, after authentication, directs the SE to unlock the doors. Then the SE uses NFC to send the key data securely.