5 a Novel 256 - Bit Block Cipher

Tornado is a novel 256-bit block cipher that accepts a variablelength key up to 256 bits. The proposed cipher was built on an idea which gives it a dynamic nature. This nature means that the cipher execution flow varies according to the user’s input key. The confusion and diffusion processes are performed based on 10 round functions named “Storm-functions”. A selection and reordering operations are performed on those functions, using a fast hashing function based on the input key. The proposed cipher has a carefully designed key scheduling algorithm. The Software implementation of the proposed cipher gives high throughput. Performance study demonstrated that, Tornado is faster than the AES by a speed-up percentage of 253%. Yet, we believe that Tornado is more secure than AES.