KIASU

KIASU is authenticated encryption scheme based on the first ad-hoc tweakable AES used in two modes. It was designed by Jérémy Jean, Ivica Nikolić and Thomas Peyrin.

Design

The ad-hoc tweakable AES is produced from AES by adding 64-bit tweak T to the first two rows of the state of AES in each round (i.e. AddRoundKey is replaced by AddRoundKey & AddTweak).

Features

• The tweakable block cipher provides 128-bit security (including related-key related-tweak attacks). The first mode greatly benefits from this as the security of the whole modes goes beyond birthday bound. The second might benefit as well (conjecture).

• Speed overhead compared to AES is minimal. The two modes are based on parallel calls of AES, thus are extremelly efficient in software.

• Easy to implement given AES code. Backwards compatible with AES (set tweak=0). Security reduction of the tweakable cipher to the security of AES.

Software

The design is fast in software in general and very fast on the processors with AES-NI support.

Speed on AES-NI enabled Intel

	Intel Sandy Bridge						Intel Haswell
	128	256	512	1024	2048	4096	128	256	512	1024	2048	4096
KIASU =	5.42	2.93	2.45	2.27	2.07	1.98	1.81	1.59	1.48	1.44	1.40	1.39
KIASU=\=	1.41	1.21	1.11	1.06	1.03	1.02	0.97	0.84	0.78	0.76	0.75	0.74

Downloads

The revised (April 2, 2014) document can be found here. The first version of the submission document can be found here.