Pushing to the limits: SNOW-Axn – a fast AEAD stream cipher in aggregated mode
Dachao Wang, Alexander Maximov, Patrik Ekdahl, T Johansson · IACR Communications in Cryptology · 2026
For future 6G, there is an anticipation that a speed of around 100 Gbps could become a requirement, a speed that most current ciphers cannot reach. Due to this, we propose a new SNOW family AEAD stream cipher called SNOW-Axn that has the capability to adopt a variable length of the key (up to 256 bits), IV/nonce (up to 224 bits) and MAC (up to 128 bits) for the three modes of operation (encryption only, integrity only, AEAD), application and/or standardisation domain separations, and other parameters. SNOW-Axn has new updated LFSR and FSM components, the feature of aggregated processing, as well as a new integrity mechanism. These changes bring a significant performance boost. We provide exampled instances called SNOW-Ax1 and SNOW-Ax4, where the latter reaches the encryption speed of 421 Gbps in pure software on a laptop-grade CPU.