Question: In a 3GPP System Architecture Evolution (SAE) security context, what is a key difference between using symmetric pre-shared keys (PSK) and certificates for establishing a one-to-one binding between a Relay Node (RN) and a USIM (USIM-RN)?
Option 1: The primary difference lies in the type of encryption used for secure channel establishment.
Option 2: The use of certificates requires a Public Key Infrastructure (PKI) and allows for dynamic assignment of identities, whereas PSK does not require PKI but necessitates manual operation for key establishment.
Option 3: Certificates are mandatory for all deployments, while PSK is optional.
Option 4: The main distinction is in the number of USIMs required on the UICC, with certificates needing two and PSK requiring only one.
Explanation: This question assesses understanding of security mechanisms in telecom networks. Option 2 is correct because it highlights the fundamental differences between using certificates and PSK for RN-USIM binding: the need for PKI with certificates, which also enables more flexible identity assignment, versus the simplicity (post-establishment) but manual nature of PSK setup, without requiring PKI.