5G SA vs 5G NSA
Non-standalone (NSA) 5G is a radio upgrade on top of a 4G core (EPC). Standalone (SA) 5G replaces the core entirely with a Service-Based Architecture (SBA). The security posture between them is nothing alike.
| Attribute | 5G SA | 5G NSA |
|---|---|---|
| Core network | 5GC (SBA + SEPP) | EPC (Diameter + DEA) |
| Subscriber ID over air | SUCI (encrypted SUPI) | IMSI (plaintext at attach) |
| Roaming edge | SEPP / N32 | DEA / Diameter |
| Authentication | 5G-AKA or EAP-AKA' | EPS-AKA |
| Key length | 128 or 256 bit | 128 bit |
| Network slicing | Native (S-NSSAI) | Not supported |
Verdict
Marketing calls both "5G". Only SA delivers the security features the standard promises. Operators quoting "5G security" on an NSA deployment are inheriting LTE's attack surface — plus a shiny new radio.