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E. Andreeva, A. Deprez, J. Bermudo Mera, A. Karmakar, A. Purnal:
"Optimized Software Implementations for the Lightweight Encryption Scheme ForkAE";
in: "CARDIS: International Conference on Smart Card Research and Advanced Applications", LNCS, volume 12609; issued by: Springer; Springer, Cham, 2021, ISBN: 978-3-030-68486-0, 68 - 83.

In this work we develop optimized software implementations for ForkAE, a second round candidate in the ongoing NIST lightweight cryptography standardization process. Moreover, we analyze the performance and efficiency of different ForkAE implementations on two embedded platforms: ARM Cortex-A9 and ARM Cortex-M0.

First, we study portable ForkAE implementations. We apply a decryption optimization technique which allows us to accelerate decryption by up to 35%. Second, we go on to explore platform-specific software optimizations. In platforms where cache-timing attacks are not a risk, we present a novel table-based approach to compute the SKINNY round function. Compared to the existing portable implementations, this technique speeds up encryption and decryption by 20% and 25%, respectively. Additionally, we propose a set of platform-specific optimizations for processors with parallel hardware extensions such as ARM NEON. Without relying on parallelism provided by long messages (cf. bit-sliced implementations), we focus on the primitive-level ForkSkinny parallelism provided by ForkAE to reduce encryption and decryption latency by up to 30%. We benchmark the performance of our implementations on the ARM Cortex-M0 and ARM Cortex-A9 processors and give a comparison with the other SKINNY-based schemes in the NIST lightweight competition - SKINNY-AEAD and Romulus.

http://dx.doi.org/10.1007/978-3-030-68487-7_5

https://publik.tuwien.ac.at/files/publik_297048.pdf