KSEAF (Key SEcurity Authentication Function) is the master security key that the SEAF (Security Anchor Function) holds for a specific UE after successful authentication in the 5G Core (5GC).
It is the root of the 5G key hierarchy that protects NAS signalling, RRC/PDCP traffic and any subsequent derived keys (e.g., KN3I, KAMF, KDN‑HN, KUP‑F) [TS 33.501 § 5.4.2].
Bit‑length: 256 bits (32 bytes) for all 5G algorithms (128‑bit key for 128‑bit crypto, 256‑bit for 256‑bit crypto).
Scope: It is bound to the SEAF identity (SN‑N), which guarantees that the key is only usable by the serving network that performed the authentication.
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