SUCI
Subscription Concealed Identifier

The SUCI is an encrypted representation of the subscriber’s SUPI (Subscription Permanent Identifier). Specifically, when the SUPI is based on an IMSI, the MSIN (Mobile Subscriber Identification Number) element is encrypted, with the MCC (Mobile Country Code) and MNC (Mobile Network Code) elements left in the clear. The device will create the SUCI and provide it to the network during Registration, at which point the UDM (Unified Data Management) will decrpyt it back to the SUPI.