5G-AKA vs EPS-AKA
EPS-AKA is the LTE authentication protocol. 5G-AKA is its 5G successor. The key change is that authentication is anchored at the home network, not the visited network — closing a class of roaming abuse.
| Attribute | 5G-AKA | EPS-AKA |
|---|---|---|
| Anchor | Home network (SEAF / AUSF) | Visited network |
| Subscriber ID | SUCI over the air | IMSI in plaintext at attach |
| Key length | 128 or 256 bit | 128 bit |
| Roaming-side control | Home network verifies UE presence | Home trusts visited assertion |
Verdict
Home-network anchoring is 5G-AKA's most underrated improvement. Combined with SUCI it closes the "fake attach from visited network" class of Diameter abuse. But it only works in 5G SA — NSA deployments fall back to EPS-AKA.