The Compression Function Start with a collision resistant compression function f f:{0,1}mt→>{O,1} where t≥2 Message of length of length So f will al ways compress a block by at least two bits 2222 f Start with a collision resistant compression function f: f: {0,1}m+t → {0,1}m where t ≥ 2 x: Message of length m+t Message of length m So f will always compress a block by at least two bits. The Compression Function