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supi in 5g

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The term "SUPI" stands for Subscription Permanent Identifier. SUPI is a unique identifier associated with a subscriber in a 5G network. The introduction of SUPI is primarily aimed at enhancing user privacy, especially when compared to its predecessor in 4G/LTE networks, the IMSI (International Mobile Subscriber Identity).

Technical Details:

  1. Purpose:
    • The main reason for introducing SUPI is to improve user privacy. In previous generations like 4G/LTE, the use of IMSI posed potential security and privacy risks as it could be intercepted or traced.
  2. Structure:
    • SUPI is a globally unique identifier assigned to each subscriber in a 5G network.
    • Unlike IMSI, which is a straightforward number, SUPI can be an encrypted value to ensure better privacy.
  3. Protection:
    • 5G networks use mechanisms such as the Security Edge Protection Proxy (SEPP) to protect the SUPI from exposure to entities outside the network.
    • SUPIs are not transmitted in clear text over the air, which helps in preventing potential eavesdropping and tracking.
  4. Mapping to IMSI:
    • For backward compatibility and interoperability with older networks and systems, there is a need to map SUPI to IMSI.
    • This mapping is done securely within the network, ensuring that external entities cannot easily correlate the SUPI to the IMSI.
  5. Authentication and Encryption:
    • When a device initiates communication with the 5G network, it undergoes authentication procedures.
    • During this process, the SUPI may be used for identification, but due to security measures, its exposure is limited.
    • Data transmitted between the device and the network is encrypted to ensure confidentiality.
  6. Home Network Security:
    • The home network (or the subscriber's home operator) maintains the mapping between SUPI and IMSI.
    • This mapping information is securely managed and is not exposed to other networks or unauthorized entities.

Benefits:

  • Enhanced Privacy: By replacing the IMSI with the SUPI and ensuring its protection, 5G networks offer improved user privacy, making it harder for malicious entities to track or intercept user activities.
  • Secure Communication: With mechanisms in place to protect the SUPI and encrypted communication channels, 5G networks provide a more secure environment for user communication and data transfer.