Selecting the Right Authentication Protocol for Your Business

Authentication protocols serve as the backbone of online security, enabling users to confirm their identities securely and access protected information and services. They define how claimants (users trying to access a digital service) and verifiers (the entities authenticating them) communicate. The protocols exchange information to verify the validity of the authentication service and confirm that the claimant possesses the appropriate token to authenticate their identity.

With myriad authentication protocols available, however, selecting the appropriate one for your organization can be daunting. Following are the key authentication protocols, along with insights into choosing the right one for your business needs.

The Authentication Protocol Landscape

Each authentication protocol offers unique features tailored to specific use cases and security requirements. If you're trying to figure out which one is best for your business, consider these four authentication protocols and their potential use cases.

OAuth/OpenID Connect (OIDC): OAuth, primarily designed for authorization, allows users to grant third-party applications limited access to their private resources without revealing their credentials. You might consider using OAuth from providers such as Google and GitHub to prioritize quick user registrations while getting validated information.

OpenID Connect (OIDC) is an open standard that builds on OAuth by providing authentication capabilities using an ID token to verify user identity securely. OIDC suits scenarios in which interoperability and user authentication across multiple systems are crucial, such as in federated identity management systems.

Both OAuth and OpenID Connect are widely adopted, allowing for interoperability between different systems, and they let users authenticate once to use the same credentials across multiple services. OAuth and OpenID Connect are, however, susceptible to phishing attacks and token theft if not implemented securely.

Security Assertion Markup Language (SAML): SAML is an XML-based standard for exchanging identity information between the user, the identity provider (IdP), and the service provider (SP). SAML offloads authentication responsibilities to specialized IdPs, reducing the burden on SPs and enhancing security. SAML works best for single sign-on (SSO) authentication in enterprise environments, where centralized authentication and access control are essential.

SAML supports use cases like identity federation, but SAML configurations can be complex and require careful management. SAML's reliance on XML may also introduce complexity owing to it being an older format than more modern ones, like JSON.

FIDO2/WebAuthn: FIDO2 is an open standard for passwordless authentication that relies on registered devices or hardware security keys to verify user identities. WebAuthn, a component of FIDO2, enables passwordless authentication through possession-based and biometric methods. You may want to consider WebAuthn for consumer-facing applications and mobile-first experiences, leveraging native device capabilities for seamless and secure authentication.

Passkeys, which are cross-device credentials based on the WebAuthn standards, have been implemented in several large organizations like Google, Apple, Shopify, Best Buy, TikTok, and GitHub over the past few years. Success stories from early adopters and increased awareness among end users are sure to continue driving adoption in the years to come.

FIDO2 and WebAuthn provide strong security against phishing and other attacks — because they don't rely on shared secrets like passwords — and a user-friendly experience, because users don't need to remember complex passwords. That said, FIDO2 and WebAuthn aren't compatible with all devices and browsers; current support gaps might make these protocols cumbersome for some users.

Time-Based One-Time Password (TOTP): TOTP generates single-use passcodes based on a shared secret key and the current time, often providing an additional layer of security in multifactor authentication (MFA) setups. TOTP supports both hardware tokens and software-based authenticator applications. You should consider TOTP for various authentication scenarios that require enhanced security.

TOTP provides an additional layer of security beyond a password, as the code changes frequently and is tied to the specific device generating it. TOTP does, however, require the user to have a separate device to generate the codes, and it doesn't protect against phishing if the user is tricked into handing the code over to the attacker.

Factors in Selecting an Authentication Protocol

It's easy to generalize which of the above four protocols you should use. Business applications targeting enterprises should use SAML because of its robust SSO capabilities and centralized authentication management. Consumer and mobile applications should pick WebAuthn/passkeys to provide a seamless and secure authentication experience that leverages native device features, like biometrics.

That said, each business has unique requirements, and it's not always best to generalize. Here are some factors to keep in mind when choosing an authentication protocol:

Choosing the right authentication protocol is critical for maintaining the security and trust of your users. By understanding the features and use cases of different protocols and considering factors such as security, integration, scalability, and user experience, you can select the most suitable protocol for your organization's needs.