Sponge Construction

An alternative to Merkle Damgard Construction. Using a function that can absorb and squeeze arbitrary size data.

Construction

• With input $M=m_1||m_2||\dots ||m_n$
• With hashed output $Z=z_1||z_2||\dots ||z_n$
• With internal state comprised of $r$-bits (rate) and $c$-bits (capacity)
  • $c$ should be double the desired resistance to Hash Collision or Preimage Attack