This is my old project (from 2004-2005 years), which implements arbitrary precision integer arithmetic. The code is provided as-is, without any modifications since the 2005 year. It consists of the following parts: * A C library for arbitrary presision arithmetic. It is located in the libbig_int folder. * A command-line simple calculator based on the libbig_int. It is located in the libbig_int/projects/calc folder. * A PHP wrapper for libbig_int library. It is located in the root folder. The wrapper is published at http://pecl.php.net/package/big_int . * Crypt_RSA - a PoC implementation of RSA encryption and code signing in PHP. It is located in the PEAR folder. The implementation is published at http://pear.php.net/package/Crypt_RSA .