Hash Function Requirements

• H can be applied to a block of data of any size

• H produces a fixed length output

• H(x) is relatively easy to compute

• For any given code h, it is computationally infeasible to find x such that H(x) = h

• For any given block x, it is computationally infeasible to find y  x with H(y) = H(x)

• It is computationally infeasible to find any pair (x,y) such that H(x) = H(y)