Which of the following is an XML based open standard used in the exchange of authentication and authorization information between different parties?

LDAP (Lightweight Directory Access Protocol) is a protocol for querying and modifying directory services like Active Directory; it is not XML-based and is not designed to exchange authentication assertions between different federated parties.

SAML is an OASIS open standard that uses XML to encode security assertions - statements about a subject's identity, attributes, and authorization decisions - and passes them between an Identity Provider (IdP) and a Service Provider (SP). It is the foundation of many enterprise Single Sign-On (SSO) implementations, allowing users to authenticate once and access multiple federated services. SAML 2.0 is the current widely-adopted version.

TACACS+ is a Cisco-developed AAA protocol that uses TCP and its own binary encoding, not XML, and is designed for centralized device administration rather than federated identity exchange.

Kerberos is a ticket-based network authentication protocol that operates using binary tickets and symmetric cryptography, not XML, and is designed for authentication within a single domain or realm.