Section: 6.12.5 Subscription identifier de-concealing function (SIDF)
Content: SIDF is responsible for de-concealing the SUPI from the SUCI. When the Home Network Public Key is used for encryption of SUPI, the SIDF shall use the Home Network Private Key that is securely stored in the home operator's network to decrypt the SUCI. The de-concealment shall take place at the UDM. Access rights to the SIDF shall be defined, such that only a network element of the home network is allowed to request SIDF. NOTE: One UDM can comprise several UDM instances. The Routing Indicator in the SUCI can be used to identify the right UDM instance that is capable of serving a subscriber.