You can make single sign on authentication more secure by enabling secure sockets layer (SSL). This security method helps to create safe connections when transmitting data over unsecured networks, such as the internet. You may also use SSL internally to ensure data transmitted over your intranet remains protected. SSL establishes a link between the user and server through encryption.
For Sensitive Corporate Data Use Two Factor Authentication in Place of Single Sign on Authentication
While SSL does help to improve the security of single sign on authentication it may not always be your best option for your more sensitive data. In situations where you want to protect your employees’ personal information, payroll data, financial data and proprietary data you might want to consider using two factor authentication. This type of authentication requires users to supply something they know along with something they possess, like their user ID, password and a digital certificate.