Transport workers and logistics drivers operating electric delivery vehicles and freight trucks depend on charging infrastructure that is authenticated through vehicle-to-grid (V2G) protocols. This paper audits a widely cited ECC-based V2G authentication framework and exposes four structural vulnerabilities that directly threaten transport worker fleet operations: an executability gap in online verification steps where verifiers cannot reconstruct stated check values from transmitted messages, ecosystem-wide credential exposure triggered by a single service-provider compromise, timestamp-only freshness that permits replay attacks within clock-drift tolerances, and a session key assembled from static identifiers without a fresh ephemeral secret. A targeted redesign is proposed that retains the original three-party architecture while introducing nonce-bound ECC key agreement, rotating pseudonyms, and station-scoped authorization tickets. Evaluated across 100 to 800 concurrent vehicles, the revised protocol achieves complete replay detection and substantially improved compromise containment with a latency overhead of only 1.8 ms at peak load.

• 변해원(한국기술교육대학교 고용서비스정책학과, 한국기술교육대학교 미래융합학부) | Haewon Byeon (Professor, Department of Future Technology, Korea University of Technology and Education (KOREA TECH).) Corresponding author
• 금창민(한국기술교육대학교 고용서비스정책학과) | Keum Chang-min
• 최기성(한국기술교육대학교 고용서비스정책학과) | Choi Ki Sung
• 장신철(한국기술교육대학교 고용서비스정책학과) | Jang Sin-cheol