Mutual authentication

Definition
Mutual authentication is

"a process whereby customer identity is authenticated and the target Web site is authenticated to the customer."

Financial institutions
"Currently, most financial institutions do not authenticate their Web sites to the customer before collecting sensitive information. One reason phishing attacks are successful is that unsuspecting customers cannot determine they are being directed to spoofed Web sites during the collection stage of an attack. The spoofed sites are so well constructed that casual users cannot tell they are not legitimate. Financial institutions can aid customers in differentiating legitimate sites from spoofed sites by authenticating their Web site to the customer."