We propose to model the dynamics, on AdS_2 near horizon geometries
of extremal BH,by chaotic maps (Arnold cat maps).
At the classical level the zero temperature BH entropy, can be represented
by the dynamic entropy of appropriate, ergodic and strongly mixing,
chaotic maps ,which is defined by their Liapunov exponents.
At the quantum level , properties of the maps,similar to the celebrated
factorization Shor's algorithm,guarantee the saturation of the
scrambling time bound for the superdifusion of the quantum
information(qudits).