How SSO Tokens Work, Main Types, and Security Considerations

Single-sign on (SSO) is becoming more and more common in busy and complex B2B setups, where users have to log into dozens of accounts multiple times daily. This productivity and satisfaction booster is powered by SSO tokens. Let’s take a closer look at how they work.

What Are SSO Tokens? 

The SSO token (single sign-on token) is a digital authentication credential that allows users to access multiple applications and services using a single set of login credentials. This simplifies the user experience, because users don’t need to remember multiple usernames and passwords. It also enhances security through centralized authentication management.

As organizations increasingly rely on a large number of SaaS applications and services, managing separate logins for each of them can be burdensome and increase the risk of unauthorized access due to weak or reused passwords. By implementing SSO tokens in your organization, you can provide a seamless experience for your users while maintaining strong security measures.

In this article:

How SSO Tokens Work 

Step 1: User Authentication

The process starts when users try to access an application that is part of an SSO-enabled environment. The Identity Provider (IdP) requests authentication details, such as a username and password, from the users. The IdP then prompts the users for their login credentials.

Step 2: Token Generation

After authentication, the IdP generates an SSO token containing user identity information and any additional attributes required by Service Providers (SPs). The SSO token serves as confirmation that an authorized entity has authenticated the user.

Step 3: Token Validation and Authorization

  • Token transmission: The IdP sends the token back to the browser via HTTP redirect or POST binding method and then forwards it to the SPs.
  • Token verification: Each SP validates the received token using its Public Key Infrastructure (PKI) before granting access based on predefined policies established during integration between SPs and IdPs.
  • Authorization: After successful validation, the SP authorizes and allows user access to its resources based on the permissions and roles.

Once authenticated, users can freely navigate applications within the same environment without re-entering their credentials.

Learn more in our detailed guide to SSO as a service (coming soon)

Types of SSO Tokens 

SAML (Security Assertion Markup Language) Tokens

SAML tokens are XML-based security tokens containing assertions about a user’s identity, attributes, and entitlements. They are commonly used in enterprise environments for web-based single sign-on between different domains or organizations.

OAuth Tokens

OAuth tokens, also known as access tokens or bearer tokens, enable clients to securely access protected resources on behalf of an end-user without directly sharing their credentials with the client application. OAuth is widely adopted by many popular APIs, such as Google API Suite and Facebook Graph API.

JSON Web Tokens (JWT)

JSON Web Token (JWT) is a compact, URL-safe way of representing claims about an authenticated user. JWTs can be transferred between two parties. They are typically signed using a secret key or public/private key pairs for added security measures, like integrity verification and authentication purposes. JWTs are often used in modern web applications and APIs for authentication and authorization.

Kerberos Tickets

Kerberos tickets are part of the Kerberos protocol, a network authentication system that uses symmetric key cryptography to authenticate users within a trusted environment. It is widely used in Windows-based environments and other platforms supporting the Kerberos protocol.

WS-Federation Tokens

WS-Federation tokens, also known as WS-Trust tokens, are SOAP-based security tokens that provide claims about an authenticated user’s identity, attributes, and entitlements. They were developed by Microsoft primarily for use with their Active Directory Federation Services (ADFS) platform but can be implemented on other systems as well.

Securing SSO Tokens 

Data Encryption

Encrypting the token payload ensures that even if attackers intercept it, they cannot read or manipulate its contents. Different types of encryption algorithms can be used depending on the specific token type. For example, JSON Web Encryption (JWE) can be applied for JSON Web Tokens (JWT), while XML Encryption is suitable for SAML tokens.

Digital Signature

A digital signature helps verify the authenticity and integrity of a token by using cryptographic techniques, such as public key cryptography. The issuer signs the token with their private key, allowing recipients to validate it using a corresponding public key. JWTs use JSON Web Signature (JWS), whereas SAML uses the XML Digital Signature (XMLDSig) standard.

TLS/SSL Communication Channels

Always use secure communication channels like Transport Layer Security (TLS) or Secure Socket Layer (SSL) to prevent eavesdropping or man-in-the-middle (MitM) attacks during transmission between parties involved in an SSO process. These protocols ensure encrypted connections between clients and servers when exchanging sensitive information, such as access tokens.

Token Expiration and Refreshing Mechanisms

  • Token expiration: Implementing short-lived tokens reduces the risk of unauthorized access if a token is compromised. Once expired, the token becomes useless and cannot be used for authentication.
  • Refresh tokens: To maintain user sessions without requiring re-authentication, use refresh tokens that can request new access tokens when needed. This approach allows you to revoke or update permissions without impacting active sessions.

Auditing and Monitoring

Maintaining an audit trail of SSO events helps identify suspicious activities and potential security breaches in your system. Regularly monitoring these logs enables a prompt response to any detected threats or vulnerabilities. Tools like Logstash, Splunk, or cloud-based solutions such as AWS CloudTrail can assist with log management and analysis.

SSO with Frontegg 

Once you integrate Frontegg’s self-served SSO solution, your customers can configure their SSO flows completely on their own with no frustrating support tickets and in-app friction. All it takes is a few lines of code and you are on your way. These flows can be integrated with leading protocols like SAML and OIDC. Yes, we also offer smooth social login integration for added customer satisfaction.

Frontegg also takes care of the front end with a fully customizable login box that saves valuable in-house development time. This dynamic box can be embedded into your SaaS offering in no time, another key component in a truly end-to-end user management solution.


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