Subscription Permanent Identifier (SUPI)
A SUPI is a 5G globally unique Subscription Permanent Identifier (SUPI) allocated to each subscriber and defined in 3GPP specification TS 23.501. The SUPI value is provisioned in USIM and UDM/UDR function in 5G Core.
Subscription Concealed Identifier (SUCI)
Subscription Concealed Identier (SUCI) is a privacy preserving identifier containing the concealed SUPI. The UE generates a SUCI using a protection scheme with the public key of the Home Network that id securely provisioned to the USIM during the USIM registration. Solution to IMSI catcher In 2G , 3G and 4G network , UE shares IMSI in plain text while initial registration. There is risk that someone can catch IMSI on radio and misuse it. But in 5G During Initial registration of UE, SUCI is used for security pupose in 5G system. This has soved the issue of IMSI catcher in 5G.