Securing time synchronization in open radio networks
Tick-Tock on the Open Fronthaul: Securing Synchronization in O-RAN
Cryptography and SecurityNetworking and Internet Architecture
Summary
Open Radio Access Networks need precise timing to work well, but their timing signals can be tricked or delayed by attackers because they aren’t properly protected. The authors explain why current security methods don’t work well with these networks’ special timing needs. They introduce a new way called PRTESLA-C to keep timing signals safe by checking them after they arrive without slowing things down. This helps maintain very accurate timing while stopping attackers from messing with the signals.
What this means in practice
- •For telecom network operators: Protect time synchronization in disaggregated radio access networks against spoofing and timing attacks without affecting network latency or accuracy.
- •For industrial control system engineers: Implement secure, low-latency time synchronization over multicast networks to improve reliability against timing signal manipulation attacks.
Authors
Yiwei Zhang, Enrico Pisanti, Imtiaz Karim, Subangkar Karmaker Shanto, Elisa Bertino
Abstract
The Precision Time Protocol (PTP) provides the time and phase synchronization required by disaggregated Open Radio Access Networks (O-RAN). Yet, in current open fronthaul deployments, PTP traffic lacks mandatory authentication and integrity protection, leaving synchronization vulnerable to spoofing, replay, and delay manipulation attacks that can degrade radio access performance. Existing protections are poorly suited to this setting: they either add excessive latency, do not support multicast dissemination efficiently, or fail to contain key exposure under partially trusted RUs. This paper analyzes the security risks of unprotected O-RAN PTP and develops a threat model for open fronthaul deployments. We then introduce PRTESLA-C, a lightweight synchronization protection mechanism that combines per-round delayed key disclosure with ASCON-based message authentication. PRTESLA-C uses an apply-then-verify-and-correct paradigm: timing samples are applied immediately to preserve real-time control, verified after key disclosure, and removed from persistent synchronization state if authentication fails. This design maintains sub-microsecond synchronization accuracy, provides strong protection against spoofing and replay, and bounds the impact of delay manipulation with minimal computational and latency overhead.