Zend_Crypt_Math_BigInteger is a wrapper across three PHP extensions: bcmath, gmp
and big_int. Since each offer similar functionality, but availability of
each differs across installations of PHP, this wrapper attempts to select
the fastest option available and encapsulate a subset of its functionality
which all extensions share in common.
This class requires one of the three extensions to be available. BCMATH
while the slowest, is available by default under Windows, and under Unix
if PHP is compiled with the flag "--enable-bcmath". GMP requires the gmp
library from http://www.swox.com/gmp/ and PHP compiled with the "--with-gmp"
flag. BIG_INT support is available from a big_int PHP library available from
only from PECL (a Windows port is not available).