Bishwajit Chakraborty, Mridul Nandi
Indian Statistical Institute, Kolkata
September 20, 2019
This work proposes ORANGE, a variant of sponge authenticated encryption and sponge hash which can
absorb data in the optimum rate. In other words, it is an Optimum RAte spoNGE construction. In this
submission, we propose an authenticated encryption, named as ORANGE-Zest and a hash function, named
as ORANGISH based on a 256-bit permutation.
Underlying Permutation. Both construction use PHOTON256 as the underlying permutation. Among
the existing 256-bit permutations, PHOTON256  is one of the lightest designs in the literature. It has been
well studied and well analysized. Moreover, PHOTON256 is also a part of ISO-IEC: 29192-5 standard, which
deal specifically with light-weight cryptography.