Efficient (HUGE) prime modulus

[Peter Otten]

blaine wrote:

>     A = (G ** a) % P # G^a mod P
> 
> ###### END #####
> The above code takes a very long time.  If I make little a only 16 bits
> instead of 512, it takes about 12 seconds on my machine to compute. Is
> this incorrect usage of **?  I used math.pow and built-in pow.  The
> math.pow complained about converting a long to a float.  The built in
> pow() took a very long time as well.

Even in its three-argument form?

"""
pow(...)
    pow(x, y[, z]) -> number
    
    With two arguments, equivalent to x**y.  With three arguments,
    equivalent to (x**y) % z, but may be more efficient (e.g. for longs).
"""

Peter