5G basics
Unified Data Management (UDM)
Description
In a 5G network, the UDM (Unified Data Management) generates authentication tokens used during the authentication and key agreement (AKA) procedure.
The generation is based on user subscription data, which it retrieves from the User Data Repository (UDR). Often co-located with the UDM is the Subscription Identifier De-concealing function (SIDF) that is used during the identification phase to resolve the Subscription Permanent Identifier (SUPI) from the Subscription Concealed Identifier (SUCI), this is explained in AKA as well.
Security importance
The UDM implements an essential security role in the 5G during the identification procedure as it implements the SIDF and also during the AKA procedure as it generates the authentication tokens for the UE authentication.