Remote Authentication Dial-In User Service (RADIUS) is an authentication protocol primarily used by network solutions such as wireless networks, VPNs, and network infrastructure devices. RADIUS servers typically connect to a central directory service that contains the user`s credentials. RADIUS was initially primarily used by ISPs and others, but has since been reused to control Wi-Fi networks and VPNs. The main distinguishing feature between these three players is that OAuth 2.0 is a framework that controls the authorization of a protected resource such as an application or set of files, while OpenID Connect and SAML are both industry standards for federated authentication. This means that OAuth 2.0 is used in fundamentally different situations from the other two standards (see examples below) and can be used simultaneously with OpenID Connect or SAML. There are as many ways to secure data as there are ways to attack it. From multi-factor authentication to single sign-on to local firewalls, the options can be mind-blowing. For developers and IT professionals, deciding how to protect data and identities starts even earlier: they choose which standard to provide to ensure federated identity security. Source: jumpcloud.com/blog/protocols-using-identity-management oauth`s comparison with ws-fed and SAML: blogs.technet.microsoft.com/askpfeplat/2014/11/02/adfs-deep-dive-comparing-ws-fed-saml-and-oauth/ Authenticating users to applications is probably one of the biggest challenges for IT. There are many different systems that a user needs to access, and that`s why authentication protocols are usually open standards – we introduce the five most commonly used. When you read questions about the “correct authentication protocol” on Stackoverflow, such as “Could you help me determine which authentication protocol I should use for the next use case?” It becomes abundantly clear that this can be an overwhelming topic. Tech Republic and others have done a great job of summing up the chaos of suppliers and standards.

FIDO2 Projecten.wikipedia.org/wiki/FIDO2_ProjectThe FIDO2 project is a joint effort of the FIDO Alliance and the World Wide Web Consortium (W3C) to create strong authentication for the Web. At its core, FIDO2 consists of the W3C Web Authentication (WebAuthn) standard and the FIDO Client to Authenticator Protocol 2 (CTAP2). FIDO2 is based on previous work of the FIDO Alliance, in particular the Universal 2nd Factor Authentication (U2F) standard. The access token is used for authentication and authorization to access resources from the resource server. Source: docs.microsoft.com/en-us/openspecs/windows_protocols/ms-adfsod/e29e94c8-2e59-45ae-9b1c-943de1966ae8 We also have a more targeted comparison between SAML and OAuth in another article, if that`s what you`re looking for. While virtually all directory servers support LDAP, some servers support additional protocols that can be used to interact with data. Some of these protocols include X.500 (the original directory access protocol, for which LDAP is a much lighter version), naming service protocols such as DNS and NIS, HTTP-based protocols such as DSML and SCIM, and proprietary protocols such as Novell`s NDS. The RADIUS server then verifies the accuracy of the information using authentication schemes to validate the data. To do this, the information provided by the user is compared to a database stored locally or referenced to external sources such as Active Directory servers. The main advantage of Windows networks is the ability to automatically connect users to all resources connected to the domain.

With the constant shift to SaaS applications, Kerberos has become a less important authentication protocol, but it is still widely used by Microsoft for its local domain controller. It`s also important to note that with the changing IT landscape, many organizations have moved from an on-premises domain to an enterprise architecture without a domain, making Kerberos slightly less relevant than a decade ago. NTLM authentication is still supported and should be used for Windows authentication with systems configured as members of a workgroup. NTLM authentication is also used for local logon authentication on non-domain controllers. Kerberos version 5 authentication is the preferred authentication method for Active Directory environments, but a non-Microsoft or Microsoft application can still use NTLM. LDAP, the lightweight Directory Access Protocol, is a mature, flexible, and well-supported standards-based mechanism for interacting with directory servers. It is often used for authentication and storing information about users, groups, and applications, but an LDAP directory server is a fairly universal data store and can be used in a variety of applications. Kerberos is a LAN authentication and authorization protocol for single sign-on organizations.

Essentially, it`s like SAML, but not for the Internet. The simple and protected GSSAPI trading mechanism (SPNEGO), often pronounced “spenay-go”, is a GSSAPI “pseudo-mechanism” used by client-server software to negotiate the choice of security technology. SPNEGO is used when a client application wants to authenticate to a remote server, but neither end is secure of the authentication protocols supported by the other. The pseudo-mechanism uses a protocol to determine which common GSSAPI mechanisms are available, selects one, and then sends all other security operations to it. .