Introduction
Authentication lies at the heart of secure digital systems. As organizations continue to migrate toward cloud-first, API-driven, and mobile-friendly architectures, the methods we use to verify identity must evolve. For decades, protocols like LDAP, RADIUS, Kerberos formed the backbone of enterprise authentication. Today, however, modern alternatives, SAML and OIDC, have emerged as gold standards. And with them comes another shift: from on-premise identity providers (IdPs) to cloud-based solutions.
In this post, we'll explore why SAML and OIDC outperform legacy protocols in today’s environments and why cloud-based IdPs are now the preferred model for secure, scalable authentication
The Limitations of Legacy Authentication
Before we look at where authentication is going, it’s worth understanding where it's been. Legacy protocols like LDAP, RADIUS, Kerberos, and NTLM were foundational to enterprise IT, but they were built for a time when networks were centralized, users were on-site, and applications lived in the data center.
- LDAP (Lightweight Directory Access Protocol) is a method for querying and modifying directory services and underpins many authentication systems (like Active Directory).
- RADIUS (Remote Authentication Dial-In User Service) was designed for authenticating remote users connecting to network services.
- Kerberos, a ticket-based system developed at MIT, brought significant improvements in security through mutual authentication and session tickets.
- NTLM (NT LAN Manager) is a challenge-response authentication protocol developed by Microsoft as a predecessor to Kerberos.
Why These Protocols Struggle Today:
- On-premises assumptions: Most were designed assuming a single, secure corporate network perimeter. Today’s perimeter is porous, or nonexistent.
- Poor support for federation and SSO: While Kerberos does offer SSO within a domain, extending that across modern cloud services is complex and brittle.
- Limited compatibility with cloud-native apps: These protocols don’t integrate easily with browser-based workflows, mobile apps, or modern APIs.
- Security risks: NTLM in particular is considered insecure by modern standards and is deprecated in many environments.
While still common in Windows-based networks, these protocols are increasingly a bottleneck in hybrid or cloud-first strategies. To stay agile and secure, organizations are moving to authentication protocols built for the cloud era.
Modern Authentication with SAML and OIDC
To meet the demands of modern systems, two protocols have become dominant: SAML (Security Assertion Markup Language) and OIDC (OpenID Connect).
- SAML, typically used in enterprise single sign-on scenarios, enables identity federation via XML-based assertions. It's a staple in connecting users to SaaS apps like Salesforce, Workday, and others.
- OIDC, a lightweight, modern protocol built on top of OAuth 2.0, is ideal for APIs, mobile applications, and browser-based flows. It uses JSON Web Tokens (JWTs), making it easier to parse and more flexible than SAML.
Advantages of SAML and OIDC include:
- Federated identity: Users authenticate once and gain access to multiple apps, which is crucial for both employee and partner ecosystems.
- Token-based architecture: Removes the need for direct access to the authentication server during each transaction, which reduces the risk of credential theft and replay attacks; instead, signed tokens allow for fast, secure verification.
- Support for modern security practices: MFA (multi-factor authentication), adaptive authentication, and risk-based policies are natively supported.
- Cross-platform compatibility: These protocols are designed for today’s diverse client ecosystem - whether mobile, desktop, browser, or API, a cloud-based application or an on-premises system, SAML and OIDC can provide seamless authentication across the board.
SAML and OIDC decouple identity from application logic, enabling centralized access management, better auditability, and consistent policy enforcement across services.
Identity Providers: Why Cloud Beats On-Prem
Modern protocols like SAML and OIDC are only part of the solution. Equally important is where authentication is managed. Traditionally, enterprises used on-premise IdPs like Active Directory Federation Services (ADFS). As IT environments have shifted to the cloud, these on-prem solutions have revealed serious shortcomings.
Challenges with on-prem IdPs:
- Complex to manage: Updates, patches, hardware maintenance, and high availability configurations fall on internal IT teams.
- Limited cloud and API support: Integration with modern apps often requires workarounds or middleware.
- Poor accessibility: Providing secure access to remote workers or partners can involve clunky VPNs or firewall exceptions.
In contrast, cloud-based IdPs such as Okta, Azure AD, Auth0, and Google Workspace are built from the ground up to handle modern authentication scenarios. The adoption of SaaS-based IdPs has been driven by several compelling advantages:
- Scalability and reliability: Built-in redundancy, autoscaling, and 99.9%+ uptime guarantees are the norm. The scalability is coupled with cost efficiency, as organizations can avoid the upfront capital investment in hardware and ongoing maintenance costs.
- Accessibility and Remote Access: SaaS-based IdPs provide remote access, allowing users to authenticate from anywhere. This is particularly beneficial for distributed teams and remote workers, ensuring secure access to resources regardless of location.
- Better security: SaaS providers often have dedicated security teams and adhere to stringent compliance standards, ensuring robust security measures. This means continuous updates, proactive threat detection, and zero-trust capabilities like device and location awareness.
- Faster time-to-value: No infrastructure setup or maintenance - get up and running in days, not months.
By combining modern protocols with a cloud-based IdP, organizations gain a secure, flexible, and future-ready authentication stack.
While on-premises solutions offer control and customization, they come with their own set of challenges. Maintaining an on-premises authentication server requires significant resources, including hardware, software, and personnel. Performance can be better for local users due to reduced latency, but this advantage is often outweighed by the benefits of SaaS-based IdPs.
SaaS-based IdPs provide a more efficient and scalable solution for modern organizations. They offer the flexibility to integrate with various applications and services, making them ideal for businesses looking to streamline their authentication processes.
Conclusion
The digital landscape has changed. Employees expect seamless access from anywhere. Customers demand secure and frictionless login experiences. Security threats evolve daily. Legacy authentication protocols like LDAP, RADIUS and Kerberos were built for a different era. Today’s requirements for cloud integration, federated identity, mobile access, and zero-trust security demand a modern approach.
Modernizing your identity infrastructure with SAML or OIDC and leveraging the capabilities of cloud-based identity providers isn’t just a technical upgrade; it’s a strategic move. It supports agility, enhances security posture, and reduces operational overhead.
If your organization is still dependent on legacy systems, now is the time to assess your authentication strategy. The shift may involve upfront effort, but the long-term benefits are in security, scalability, and simplicity make it more than worth the investment.
If you're interested in learning more about how Radware's Alteon can help in this journey, please contact us.