TETRA Algorithm set B - Can glue mend the burst?

The new authentication suite (TAA2, as opposed to the old TAA1) features longer keys and completely new cryptographic primitives. The new Air Interface Encryption algorithms (TEA set B) consist of three new ciphers, for differing target audiences. TEA5 is intended for European emergency networks, and is the successor of TEA2. TEA6 is intended for friendly extra-european emergency and military networks, and replaces TEA3. Lastly, TEA7 is the only one available for use by critical infrastructure and other civil applications, and replaces TEA1. Initially, ETSI envisaged to keep the new algorithms secret again, once more eliminating the possibility of public scrutiny. However, following our publication, a promise was made to release the algorithms to the public for inspection. Additionally, a statement was made that TEA7 has a reduced effective strength of 56 bits. As mentioned, this algorithm is the successor to TEA1, which has an effective strength of only 32 bits, in a time where 40 bits was the maximum for freely exportable crypto. In TETRA:BURST, we presented several vulnerabilities found in the old standard. Obviously, the backdoored TEA1 algorithm is now replaced by a new cipher, and we will dive into how this works, how it can be attacked, and what the practical implications will be. Second, we previously presented a method of decrypting and injecting traffic on all network types, even those using the stronger TEA2 and TEA3 algorithms. This relies on the lack of cryptographic integrity guarantees on message - something that is still unaddressed. We discuss how this leads to issues. Lastly, TETRA:BURST described a way of decrypting the pseudonymized identities of TETRA users (first demonstrated at the 37C3), allowing for a powerful intelligence capability. We will discuss how the new standard seeks to resolve this issue. Lastly, we previously recommended caution regarding TEA3, due to a suspicious feature in its design. While no full attack will be presented, progress in its cryptanalysis was made, which we will discuss during the talk. And, there is an interesting parallel to be drawn between the suspicious quirk in TEA3 and the design of its successor, TEA6.