Disperse rotation operator DRT and use in some stream ciphers

Abstract

The rotation operator is frequently used in several stream ciphers, including HC-128, Rabbit, and Salsa20, the final candidates for eSTREAM. This is because the rotation operator (ROT) is simple but has very good dispersibility. In this paper, we propose a disperse rotation operator (DRT), which has the same structure as ROT but has better dispersibility. In addition, the use of DRT instead of ROT has shown that the quality of the output stream of all three stream ciphers was significantly improved. However, the use of DRT instead of ROT in the HC-128 stream cipher prevents the expansion of differential attacks based on LSB.