Full AES Research Articles

A new SNOW stream cipher called SNOW-V

In this paper we are proposing a new member in the SNOW family of stream ciphers, called SNOW-V. The motivation is to meet an industry demand of very high speed encryption in a virtualized environment, something that can be expected to be relevant in a future 5G mobile communication system. We are revising the SNOW 3G architecture to be competitive in such a pure software environment, making use of both existing acceleration instructions for the AES encryption round function as well as the ability of modern CPUs to handle large vectors of integers (e.g. SIMD instructions). We have kept the general design from SNOW 3G, in terms of linear feedback shift register (LFSR) and Finite State Machine (FSM), but both entities are updated to better align with vectorized implementations. The LFSR part is new and operates 8 times the speed of the FSM. We have furthermore increased the total state size by using 128-bit registers in the FSM, we use the full AES encryption round function in the FSM update, and, finally, the initialization phase includes a masking with key bits at its end. The result is an algorithm generally much faster than AES-256 and with expected security not worse than AES-256.

Unbalanced biclique cryptanalysis of a full round Midori

Midori is a family of lightweight block ciphers presented by Banik et al . at Asiacrypt 2015. Biclique cryptanalysis is a typical key-recovery attack that is proposed to attack the full AES by Bogdanov et al . in ASIACRYPT 2011. The method can attack a great deal of ciphers utilising the main idea of MITM attack and the basic principle of the biclique structure. In this study, the authors first provide an unbalanced biclique attack on full round Midori with partial matching and precomputation. They demonstrate that full round Midori64/128 are not secure against unbalanced biclique attacks. They construct a five-round 4×8 unbalanced biclique on Midori64, with data complexity of 2 36 and time complexity of 2 126.25 by investigating the simple key schedule and the encryption structure. Furthermore, they present a four-round 8×16 unbalanced biclique on Midori128 with data complexity of 2 72 and computational complexity of 2 126.91 . To the best of authors' knowledge, the result is the best single-key cryptanalytic result of Midori.

English

English