Table 1 Comparative Analysis of Authentication and Key Agreement Schemes in IoVT/IoT.

Ikram et al., 2020¹⁰

NAPV Protocol

Reduces signaling overhead for group authentication in 5G IoVT

Transmits vehicle permanent identity in plaintext; privacy risk; vulnerable to eavesdropping and MitM attacks

Yang et al., 2020¹¹

ECC-based AKA

Strong security using lightweight operations; supports initial and subsequent authentication

High computational cost; session dependency; scalability not addressed; real-time data analysis handling unclear

Agilandeeswari et al., 2021¹²

Lightweight Privacy-Preserving AKA

Fast source transmission; low energy consumption

Transmits permanent identity in plaintext; privacy vulnerabilities

Chein et al., 2021¹³

Key Transfer Protocol for Fog-enabled SIoV

Enables session key transfer between RSUs; supports vehicle handover

Potential key compromise; no forward/backward key secrecy; vulnerable to MitM attacks

Wazid et al., 2021¹⁴

Lightweight AKA

Mutual authentication; anonymity; dynamic RSU addition; untraceability

Requires secure channel for exchanging information (e.g., in-person interaction)

Bagga et al., 2021¹⁵

Blockchain-based AKA

Resilient against attacks; decentralized authentication

Scalability, latency, energy consumption, and cost concerns due to blockchain overhead

Miao et al., 2022¹⁶

Group AKA for 5G Vehicular Networks

Achieves anonymity, unlinkability, mutual authentication

Lacks forward/backward key secrecy; no key confirmation

Shang et al., 2022¹⁷

D2D Group-oriented AKA with CL-PKC

Supports anonymous, secure D2D group interactions

Complexity due to ECC and certificateless PKC; scalability not explicitly addressed

Ouaissa et al., 2022¹⁸

Enhanced 5G Group AKA

Robust against security threats; group authentication

Missing key confirmation; unlinkability issues; costly ECDH operations

Mei et al., 2022¹⁹

Pseudonym-based AKA

Provides anonymity using nonsingular elliptic curves

Limited scalability analysis; lacks detailed key management for mobility

Azees et al., 2022²⁰

Signature-based AKA

Lightweight authentication for VANETs

Focused on signatures; may not address group mobility or multi-factor attacks

Sharma & Dhiman, 2025²¹

Three-factor User Authentication

Addresses device theft & user impersonation; low computation & communication overhead

Primarily for low-cost IoT; group authentication not addressed

Sharma & Dhiman, 2025²²

IoT Security Survey

Comprehensive taxonomy of security threats; explores blockchain solutions

Review-based; no new protocol proposed; limited focus on group-based AKA

Ashrif et al., 2023–2024^25,26,27

PSLAE/SL_GAS

Lightweight authentication for 6LoWPAN & IIoT; mutual authentication; anonymity; low signaling & computation costs

Limited to IIoT & 6LoWPAN; not optimized for 5G IoVT group mobility