Securing your product:

Taxsoftware.com recommends using TDE combined with SSL to create a secure database with secure communications.  This involves issuing the commands that encrypt the entire database and implementing SSL on your web server.  Performing these measures along with proper firewall configuration will offer a great deal of security as well as keep your system in compliance with government regulations.

For more information regarding TDE:

http://msdn.microsoft.com/en-us/library/bb934049.aspx

http://msdn.microsoft.com/en-us/library/cc278098%28v=sql.100%29.aspx#_Toc189384676

For information regarding Secure Socket Layer:

http://msdn.microsoft.com/en-us/library/ms189067.aspx

TDE can be implemented on both Microsoft SQL Server and Oracle database systems and is recommended for use with the TaxDBC product. 

An example script is provided below and can be used on SQL SERVER 2008