5G • Security
SUPI
Subscription Permanent Identifier
The globally unique, permanent identity of a subscriber (equivalent to legacy IMSI), never sent unencrypted.
Technical Explanation
The SUPI is the permanent subscriber ID stored securely in the SIM/eSIM and UDM database. In commercial networks, it typically takes the form of an IMSI (MCC-MNC-MSIN). Unlike 2G/3G/4G where IMSIs were broadcast in plaintext, 5G strictly forbids transmitting the SUPI unencrypted over the air interface.
Key Functions
- Permanent, globally unique identifier of a 5G mobile subscriber
- Stored securely in tamper-resistant USIM hardware and UDM database
- Never transmitted unencrypted over the air interface, eliminating IMSI-catchers
Specifications
3GPP TS 23.501, TS 33.501
Interfaces
N1
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