A note on -Tweakable HCTR: A BBB Secure Tweakable Enciphering Scheme-

ePrint Report: A note on -Tweakable HCTR: A BBB Secure Tweakable Enciphering Scheme-

Mustafa Khairallah

Tweakable HCTR is an tweakable enciphering proposed by Dutta and Nandi in Indocrypt 2018. It provides beyond birthday bound security when each tweak value is not used too frequently. More importantly for this note, its security bound degrades linearly with the maximum input length. We show in this note that this is not true by showing a single query distinguisher with advantage $O(l^2/2^n)$ where $l$ …

bbb beyond eprint report report security value