5G • Security

K_RRCint

RRC Integrity Protection Key

Integrity key derived by gNodeB and UE from K_gNB preventing injection or tampering of RRC control messages.

Technical Explanation

Derived from K_gNB, K_RRCint is used by PDCP to calculate a 32-bit MAC-I appended to every RRC PDU. Integrity verification is mandatory for all connected RRC signaling; any message with a failing checksum is immediately discarded.

Key Functions

  • Provides mandatory integrity protection on all over-the-air RRC messages
  • Prevents rogue base stations from injecting unauthorized handover commands
  • Appends 32-bit MAC-I to PDCP headers of SRBs
Specifications
3GPP TS 33.501, TS 38.323
Interfaces
Uu

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