UICC

Universal Integrated Circuit Card (UICC) is a smart card used in mobile devices to securely store subscriber identity and credentials and to host multiple applications. It forms the secure element of a mobile device's network access, enabling authentication to the carrier's network and provisioning of service profiles.

A UICC can contain one or more applications, such as SIM (subscriber identity module), USIM (for 3G/4G networks), ISIM (for IP Multimedia Subsystem/IMS services), or RUIM (common in some CDMA networks). It uses a card manager and applet architecture, allowing multiple applications to co-exist and be selectively accessed by the device. Security is enforced through cryptographic keys and standardized interfaces, with applet management typically handled via GlobalPlatform specifications and secure channels.

The term covers both removable and embedded forms. A removable UICC is the traditional SIM card, while an embedded UICC (eUICC) is soldered into the device. The eUICC enables remote SIM provisioning and profile management, allowing users or operators to download, switch, or delete operator profiles without physically changing the card. This capability underpins eSIM technology, which is widely used in smartphones, tablets, wearables, and connected devices.

Standards and governance come from ETSI for the UICC architecture and GlobalPlatform for card management, with GSMA defining the remote provisioning and eSIM ecosystem. In practice, mobile networks rely on UICC-based credentials to authenticate subscribers, establish secure communication, and manage roaming and service access across multiple networks and devices.