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5G Identifiers SUPI and SUCI

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SUPI (Subscription Permanent Identifier):

  1. Definition:
    • The SUPI, or Subscription Permanent Identifier, is a unique identifier associated with a subscriber in a 5G network.
    • It serves as a long-term identifier for a user and is provisioned in the Subscriber Profile Repository (SPR) during the subscription process.
  2. Format:
    • The SUPI can be represented in different formats. The most common formats include the International Mobile Subscriber Identity (IMSI) or an IPv6-based identifier.
  3. IMSI Format:
    • The IMSI-based SUPI is similar to the IMSI used in 4G networks. It consists of three parts:
      • Mobile Country Code (MCC): A three-digit code representing the country of the mobile network.
      • Mobile Network Code (MNC): A two or three-digit code identifying the mobile network within the country.
      • Mobile Subscriber Identification Number (MSIN): A variable-length number uniquely identifying the subscriber within the network.
  4. IPv6 Format:
    • The IPv6-based SUPI is an IPv6 address assigned to the user, serving as a unique identifier.
  5. Usage:
    • The SUPI is used in various signaling procedures within the 5G network, including registration and authentication processes.

SUCI (Subscription Concealed Identifier):

  1. Definition:
    • The SUCI, or Subscription Concealed Identifier, is introduced in 5G to enhance user privacy by concealing the SUPI during certain procedures.
    • The SUCI is generated by combining the SUPI with temporary information, making it more challenging to trace back to the subscriber.
  2. Format:
    • The SUCI consists of the following components:
      • Mobile Country Code (MCC): Same as in SUPI.
      • Mobile Network Code (MNC): Same as in SUPI.
      • Routing Indicator (R): Indicates whether the SUCI is used for registration or de-registration.
      • Protection Scheme Identifier (P): Specifies the protection scheme used to conceal the SUPI.
      • SUCI Slice: A variable-length field derived from the SUPI and temporary information.
  3. Usage:
    • The SUCI is used in specific 5G procedures to replace the SUPI, providing a level of anonymity for the user.
    • It is particularly used during initial registration, where the SUCI is sent instead of the SUPI.
  4. Protection Scheme:
    • The protection scheme is chosen to determine how the SUPI is concealed within the SUCI. It could involve encryption or other cryptographic techniques to safeguard user identity.

SUPI is a long-term, permanent identifier associated with a subscriber, the SUCI is a concealed identifier used in specific scenarios to protect user privacy by hiding the SUPI. The SUCI includes additional information for security and routing purposes.