Kryptonite: sigmaAuth (σAuth)

2025: Model Presentation for Anonymous Authentication Protocol Security Analysis

In the Russian IT company Kryptonit, cryptographers presented a model for analyzing the security of anonymous authentication protocols used in 5G networks. The development, called sigmaAuth (σAuth), aims to increase the resistance of mobile networks to cyber attacks and protect the digital identity of users. The developer announced this on July 10, 2025.

The proposed model allows you to identify vulnerabilities in communication protocols and confirm their persistence using rigorous mathematical evidence. σAuth can already be used to analyze domestic decisions of 5G-AKA-GOST and S3G-5G, which, as of July 2025, are undergoing a standardization stage in the technical committee of the TK26. It is expected that the model will become the basis for further improvement of protocols that provide protection against attacks on anonymity, reuse of messages and compromise of keys.

According to the GSMA Intelligence report, at the end of 2024, the number of connections in 5G networks around the world reached 2 billion. At the same time, 5G provides connection not only to smartphones, but also to industrial systems, transport, sensors, which creates a wide attack surface. One of the vulnerable elements is the authentication process: attackers can intercept messages, track users or fake digital identifiers.

The σAuth model formalizes the concept of anonymity and takes into account scenarios in which an intruder, for example, can access IoT equipment. This is especially important when the protection of permanent identifiers such as IMSI and SUPI plays a key role in ensuring security, "said Vladimir Belsky, deputy head of the cryptography laboratory at Kryptonit.

In addition to 5G networks, σAuth can be used to design and analyze security protocols in other digital infrastructures. The model relies on the paradigm of "provable resilience," an approach that uses rigorous mathematical methods to validate the security of protocols. According to the developers, this makes it a universal and promising solution for creating new standards of cyber defense.