computeLog: g base: h modulo: p
"DiscreteLogarithm problem1"
"compute the discrete logarithm of g to the base b"
    | lookup lhs rhs B result ginv |

    B := 2 raisedTo: 20.
    ginv := g raisedTo: (p - 2) modulo: p.
    lookup := Dictionary new.
    "1. First build a dictionary of all the possible values of the left hand size of the equation h/g^x_1"
    0 to: B do: [:x1 |
        lhs := (h * (ginv raisedTo: x1 modulo: p)) \\ p.
        lookup at: lhs put: x1].

    "2. Then, for each value x_0 = 0, 1, 2, ..., 2^20 check if the right hand side (g^B)^x_0 is in the hash table"
    result := 0 to: B do: [:x0 |
        rhs := (g raisedTo: B modulo: p) raisedTo: x0 modulo: p.
        lookup at: rhs ifPresent: [:x1 | ^x0 * B + x1]].

    ^result