Which authentication protocols are commonly used in enterprise IAM?

• A. SAML, OAuth 2.0, OpenID Connect, Kerberos.
• B. FTP, SMTP, HTTP.
• C. SOAP, REST, XML-RPC.
• D. RADIUS, TACACS+, SSH.

Answer: (A)

In enterprise IAM, the aim is to securely identify users and grant appropriate access across many apps and systems, often with single sign-on and federated trust. The protocols that best support this are SAML, OAuth 2.0, OpenID Connect, and Kerberos.

SAML enables web-based single sign-on by exchanging authentication and authorization data between an identity provider and service providers. This lets users sign in once and access multiple applications without re-entering credentials, which is a cornerstone of enterprise IAM.

OAuth 2.0 provides a framework for delegated authorization. Instead of sharing passwords, applications obtain tokens that grant limited access to resources on behalf of a user, which is essential for secure API access and and third-party integrations in enterprise environments.

OpenID Connect builds on OAuth 2.0 to add user authentication and identity information in a standardized way. It allows applications to verify who a user is and obtain profile details, enabling consistent login experiences across services.

Kerberos offers strong mutual authentication within a trusted domain, using tickets issued by a central Key Distribution Center. This is widely used in corporate networks, especially where Windows Active Directory or similar ecosystems are in play, for securely proving a user’s identity to services.

The other options aren’t primarily designed as authentication protocols for IAM in the same way: FTP, SMTP, and HTTP are foundational protocols for file transfer, email, and web traffic, not identity authentication. SOAP, REST, and XML-RPC are communication or API paradigms, not authentication mechanisms by themselves. RADIUS and TACACS+ cover network access and device management authentication, and SSH handles secure remote login, but they don’t represent the standard federation and identity frameworks that enterprise IAM typically relies on.