JSON Web Token vs sso: What are the differences?

Introduction

JSON Web Token (JWT) and Single Sign-On (SSO) are commonly used authentication technologies that are used to enhance security and simplify user authentication process. While both JWT and SSO provide similar functionality, they have key differences that set them apart. In this article, we will explore the main differences between JWT and SSO.

1. JSON Web Token (JWT): JWT is an open standard (RFC 7519) that defines a compact and self-contained way for securely transmitting information between parties as a JSON object. It is widely used to authenticate and authorize web and mobile applications. JWT consists of three parts: a header, a payload, and a signature. The header contains information about the type of token and the cryptographic algorithm used to sign it. The payload carries the claims or statements about the client/user, and the signature provides integrity protection and verifies the authenticity of the JWT.

2. Single Sign-On (SSO): SSO is a user authentication mechanism that allows users to log in once and gain access to multiple applications or services without the need to authenticate separately for each application. It centralizes the authentication process, making it easier for users to remember and manage their credentials. SSO is typically implemented using a centralized system known as an identity provider (IdP), which manages user identities and authenticates the user, and then provides tokens to the relying applications or services.

3. Security Mechanism: One of the key differences between JWT and SSO is the security mechanism they employ. JWT uses a signature-based mechanism, where the token is signed with a secret key or asymmetric key pair to ensure integrity and authenticity. On the other hand, SSO relies on protocols like Security Assertion Markup Language (SAML) or OpenID Connect (OIDC) to establish trust between the identity provider and relying applications.

4. Token Scope and Granularity: Another significant difference between JWT and SSO is the scope and granularity of the tokens they generate. JWT is typically used to issue access tokens that are specific to an individual resource or service. These tokens are usually short-lived and contain claims related to authorization. In contrast, SSO generates tokens that are more comprehensive and can be used for multiple services. These tokens are often long-lived and carry information about the user's identity.

5. Token Validation Process: JWT and SSO also differ in their token validation process. In JWT, the relying party can verify the integrity and authenticity of the token by checking the token signature against the secret key or public key of the token issuer. This process does not require any further network calls. In SSO, the relying applications or services need to validate the token with the identity provider using protocols like SAML or OIDC. This typically involves additional network requests and may require exchanging security tokens.

6. Deployment Flexibility: JWT and SSO also vary in terms of deployment flexibility. JWT is more versatile and can be used in both stateless and stateful architectures. It can be easily implemented in lightweight environments like mobile applications or microservices. SSO, on the other hand, requires the installation and configuration of an identity provider, making it more suitable for larger enterprise environments with complex authentication requirements.

In Summary, JWT is a token-based authentication mechanism that focuses on individual resource access and employs a signature-based security mechanism, while SSO is a centralized authentication mechanism that enables users to log in once and access multiple applications, relying on protocol-based trust establishment with the identity provider.