Cocktail - An ARX based Cryptographic Hash Function Designed using Modified ChaCha Core

Cryptographic Hash functions are extensively used to achieve multiple security goals like message integrity and authentication. In this paper, we propose a new simple, flexible and efficient cryptographic hash function - Cocktail, that blends security with speed. Cocktail makes use of Addition, Rotation and XOR operations only and is based on Modified ChaCha core as its core primitive. Cocktail can work on 32-bit as well as 64-bit word size and generate hash output of variable sizes. Cocktail can be used in different other operating modes like HMAC, Randomized hashing, PRF ensemble etc. Cocktail can achieve considerably high level of parallelism. This paper presents the Cocktail's specifications, design philosophy, security aspects, usage and performance comparison with SHA-3 winner and other SHA-3 finalists.