Many encryption algorithms depend on the ability to raise large integers to a power. Here is a method that implements an efficient algorithm for integer exponentiation:

public static int pow$($int x$,$ int n$)$

$\{$

if $($n $==0)$ return $1$;

$//$ find x to the n$/2$ recursively

int t $=$ pow$($x$,$ n $/2)$;

$//$ if n is even, the result is t squared

$//$ if n is odd, the result is t squared times x

if $($n $\%2==0)\{$

return t $*$ t;

$\}$ else $\{$

return t $*$ t $*$ x;

$\}$

$\}$

The problem with this method is that it works only if the result is small enough to be represented by an int. Rewrite it so that the result is a BigInteger. The parameters should still be integers, though.