What is SSO?

Single Sign-On (SSO) is a user authentication mechanism that simplifies access to multiple applications and services with a single set of login credentials - for example, a username and password- . It streamlines the authentication process, allowing users to log in once and gain access to a network of interconnected systems without the need to re-enter their credentials for each individual application. SSO enhances user experience, improves productivity, and simplifies identity management for both users and IT administrators.

Benefits of SSO

• Improved User Experience: SSO eliminates the need for users to remember multiple sets of credentials for different applications, reducing password fatigue and the likelihood of password-related issues.
• Increased Productivity: With a seamless login experience, users spend less time on authentication tasks, leading to increased productivity and efficiency in their daily workflows.
• Simplified Identity Management: SSO allows IT administrators to manage user identities and access rights from a central location, streamlining user provisioning and deprovisioning processes.
• Lower Support Costs: SSO reduces the number of password-related support requests, resulting in cost savings for IT support teams.

Is SSO Secure? 

It depends. SSO simplifies login management and can enhance security by enforcing password complexity and MFA. However, some applications may require additional authentication or network restrictions.

How Does SSO Work?

SSO operates based on trust relationships between the service provider (application) and the identity provider. These trust relationships are often established through certificates exchanged between the two parties, ensuring secure communication and data exchange.

The login flow typically follows these steps:

1. A user attempts to access an application or website (service provider).
2. The service provider sends a token containing user information (e.g., email address) to the SSO system (identity provider) to request authentication.
3. If the user has already been authenticated, the identity provider grants access to the service provider, skipping further steps.
4. If the user hasn't logged in, the identity provider prompts the user to provide credentials (username/password or other authentication methods).
5. After validating the credentials, the identity provider sends a token back to the service provider, confirming successful authentication.
6. The user is granted access to the service provider.

For subsequent access to other websites or applications, the same trust relationship is used, and the authentication flow follows similar steps.

Implementing SSO

In a typical SSO implementation, a centralized identity provider (IDP) acts as a trusted authentication service. When a user attempts to access an application or service, they are redirected to the IDP's login page. The user then enters their credentials (username and password) on the IDP's page.

After successful authentication, the IDP issues a security token to the user, indicating that they are authenticated. This token is used as proof of the user's identity and authorization for accessing specific resources.

When the user attempts to access another application within the same SSO ecosystem, the application relies on the security token issued by the IDP for authentication. The application trusts the IDP to have verified the user's identity and grants access without requiring the user to log in again.

Related Terms

• Multifactor Authentication (MFA)
• Identity Provider (IDP)
• OAuth (Open Authorization)

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