Which type of authentication requires both ends to authenticate each other?

Mutual authentication is the process where both parties involved in a communication verify each other's identities before exchanging sensitive information. This is essential in establishing a trusted connection between two entities, such as a user and a server, ensuring that both the client and the server are legitimate and authorized to engage in the transaction.

In mutual authentication, not only does the server verify the identity of the client, but the client also verifies the server's identity. This two-way process helps to prevent man-in-the-middle attacks and builds a secure environment for data exchange. It is particularly important in scenarios where sensitive data is being transmitted, as it helps prevent unauthorized access and ensures that users are communicating with a trusted source.

On the other hand, options like Single Sign-On focus on convenience by allowing users to log in once for multiple services without requiring re-authentication, while Multifactor Authentication involves using more than one method of authentication (like something the user knows plus something they have) but does not necessarily involve both parties verifying each other. Strong Authentication emphasizes the use of robust methods but does not specifically imply a mutual verification process.