Which of the following is a standard authentication method used in Identity Management?

The correct choice is Security Assertion Markup Language (SAML) 2.0. SAML is a widely adopted standard for enabling single sign-on (SSO) across different domains, allowing users to authenticate with their identity provider (IdP) and gain access to various services without needing to log in multiple times. It facilitates the exchange of authentication and authorization data between parties, particularly between the identity provider and service providers (SPs), making it a pivotal method for identity management in enterprise environments.

SAML 2.0 provides a secure, standardized way to implement federated identity management, thus enhancing security and user experience. Its XML-based format ensures that assertions about user identities can be transmitted over the web securely. Given its robustness in handling authentication and its broad acceptance in enterprise applications, SAML 2.0 is fundamentally key to modern identity management practices.

The other methods listed do not serve as standard authentication methods in identity management to the same extent. For instance, while Simple Authentication and Security Layer (SASL) is a protocol that provides a framework for authentication, its usage is generally lower in comparison to SAML in terms of identity management. Protocol Buffer Encoding and XML do not comprise any authentication method but rather serve as data interchange formats