Introduction: This analysis examines vulnerabilities discovered in the TETRA (Terrestrial Trunked Radio) standard, a European radio standard used by military and police forces, as detailed in a Schneier.com article. The TETRA standard, which has been in use since the 1990s, incorporates encryption algorithms that were previously kept proprietary and secret, contributing to the delayed public awareness of these flaws.
In-Depth Analysis: The core of the issue lies in five vulnerabilities identified within the encryption algorithms of the TETRA standard by three Dutch security analysts: Carlo Meijer, Wouter Bokslag, and Jos Wetzels, from the security firm Midnight Blue. These vulnerabilities were present in radio systems manufactured by companies such as Motorola, Damm, Hytera, and Sepura. The proprietary nature of the TETRA encryption algorithms, as established by ETSI (European Telecommunications Standards Institute), prevented public scrutiny for decades, thereby concealing these weaknesses until their recent disclosure. The article highlights that the flaws remained unknown publicly until the disclosure by Meijer, Bokslag, and Wetzels. The proprietary nature of the algorithms meant that ETSI had refused for decades to allow examination of these algorithms.
Pros and Cons: The primary strength of the TETRA standard, from a security perspective prior to this disclosure, was the perceived security offered by its encryption, which was not publicly understood or auditable. This secrecy, however, proved to be a significant weakness. The lack of transparency meant that vulnerabilities could persist undetected for an extended period, potentially compromising the communications of critical services like military and police. The “pro” of secrecy in this context was the initial assumption of security, while the “con” was the actual absence of verifiable security due to the inability to audit the algorithms. The disclosure of these vulnerabilities by Midnight Blue represents a significant step towards understanding and addressing these security gaps.
Key Takeaways:
- Five vulnerabilities have been discovered in the TETRA (Terrestrial Trunked Radio) standard’s encryption algorithms.
- These vulnerabilities were identified by Dutch security analysts Carlo Meijer, Wouter Bokslag, and Jos Wetzels of Midnight Blue.
- TETRA is a European radio standard used by military and police, with systems in use since the 1990s.
- Manufacturers of TETRA-compliant radios include Motorola, Damm, Hytera, and Sepura.
- The encryption algorithms used in TETRA were proprietary and kept secret by ETSI for decades, preventing public examination and the early discovery of these flaws.
- The disclosure of these vulnerabilities, as reported on Schneier.com, highlights the risks associated with proprietary and un-auditable security standards.
Call to Action: Educated readers should monitor further developments regarding the remediation of these TETRA vulnerabilities. It is also advisable to observe how ETSI and manufacturers respond to this disclosure, particularly concerning the transparency and auditability of future encryption standards. Understanding the implications for secure communications in critical infrastructure sectors is paramount.
Annotations/Citations: The information presented in this analysis is derived from the article “Encryption Backdoor in Military/Police Radios” available at https://www.schneier.com/blog/archives/2025/08/encryption-backdoor-in-military-police-radios.html. Specifically, the discovery of five vulnerabilities in the TETRA standard by Carlo Meijer, Wouter Bokslag, and Jos Wetzels of Midnight Blue, and the role of ETSI in keeping the encryption algorithms proprietary and secret for decades, are attributed to this source.
