Crypt_RSA pear.php.net Encryption PHP Provides RSA-like key generation, encryption/decryption, signing and signature checking. Users are strongly advised to migrate to phpseclib's Crypt_RSA; which is better maintained and less vulnerable to security issues. This package allows you to use two-key strong cryptography like RSA with arbitrary key length. It uses one of the following extensions for math calculations: - PECL big_int extension ( http://pecl.php.net/packages/big_int ) version greater than or equal to 1.0.3 - PHP GMP extension ( http://php.net/gmp ) - PHP BCMath extension ( http://php.net/manual/en/ref.bc.php ) for both PHP4 and PHP5 phpseclib.sourceforge.net Crypt_RSA