SMASH (hash)

Input: 256/512-bit message blocks ${\displaystyle m_{1},m_{2},...,m_{t}}$ and ${\displaystyle \theta \in GF(2^{n})}$

• ${\displaystyle h_{0}=f(iv)\oplus iv}$
• ${\displaystyle h_{i}=h(h_{i-1},m_{i})=f(h_{i_{1}}\oplus m_{i})\oplus m_{i}\oplus \theta m_{i}}$
• ${\displaystyle h_{t+1}=f(h_{t})\oplus h_{t}}$

The function f is a complex compression function consisting of H-Rounds and L-Rounds using S-boxes, linear diffusion and variable rotations, details can be found here ^[3]

The S-boxes in SMASH are derived versions from the Serpent ones.