ETSI agrees to release TETRA algorithms to the public domain

The European Telecommunications Standards Institute (ETSI) has announced that at a recent meeting of its technical committee in charge of the TETRA standard (TCCE), a full consensus was reached to make the primitives of all TETRA Air Interface cryptographic algorithms available to the public domain. Brian Murgatroyd, Chair of ETSI TCCE, said the meeting was well attended by a wide spread of the TETRA community — including operators, users, manufacturers and governments.

“Following publication of the algorithms, we are open to academic research for independent reviews,” he said.

Making the algorithms public was discussed following the discovery earlier this year of five vulnerabilities in the original TETRA Air Interface security design (including algorithms) by Dutch security researchers. Keeping cryptographic algorithms secret was common practice in the early 1990s when the original TETRA algorithms were designed, but public-domain algorithms are now widely used to protect government and critical infrastructure networks, for example AES (the Advanced Encryption Standard, standardised by the US Government). Effective scrutiny of public-domain algorithms allows for any flaws to be uncovered and mitigated before widespread deployment occurs.

TETRA has an original set of Air Interface cryptographic algorithms — TEA1, TEA2, TEA3 and TEA4 — some of which were disclosed by the researchers. In 2022 ETSI introduced TEA5, TEA6 and TEA7 in order to futureproof the technology against quantum attacks. The entire set of these original and additional algorithms will be made available in the public domain as well as TAA1 (the original authentication and key management specification) and TAA2 (the new authentication and key management specification). This work will be carried out with the support of TCCA, the global representative organisation responsible for the enhancement of the TETRA standard.

With more than 120 countries using dedicated TETRA networks for mission- and business-critical communications, ETSI said it is continually evaluating standards and procedures to ensure the TETRA standard remains robust in the face of evolving threats, with an ongoing program of maintenance to ensure standards remain fit for purpose in an evolving security landscape.

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