What Is JWT Authentication? How Does It Work?

Robert MacDonald

Authentication is a crucial part of any web application, as it verifies the identity of the user and controls access to protected resources. One popular authentication method is JSON Web Token (JWT), which allows for secure and scalable identity verification via stateless authentication.

What Is JSON Web Token Authentication?

JSON Web Token (JWT) authentication is a stateless method of securely transmitting information between parties as a JavaScript Object Notation (JSON) object. It is often used to authenticate and authorize users in web applications and APIs.

In the authentication world, “stateless” means a mechanism in which the server does not maintain any session state between requests. In a stateless authentication system, each request is self-contained and includes all the necessary information to authenticate and authorize the user or entity. In the case of JWT authentication, this comes in the form of a token.
A JSON token consists of three parts:

  • A Header containing information about the type of token and algorithms used to generate the signature.
  • A Payload containing the “claims” (ID and authentication verifications) made by the user that can include a User ID, the user’s name, an email address, and metainformation about the operation of the token.
  • A Signature, or cryptographic mechanism, is used to verify the token’s integrity.

Together, the header, payload, and signature make up the JSON Web Token, typically passed between the client and the server in the HTTP Authorization header or in the body of an HTTP request or response. The server can then verify the signature to ensure that the token is valid and has not been modified and use the information in the payload to authenticate the user.

Here’s how JWT authentication works:

  • User Login: The user provides their credentials (such as a username and password) to the web application or system for verification, which is transmitted to the authentication server.
  • Token Generation: Upon successful authentication, the server generates a JSON token containing critical information about the user and the authentication session. The server sends the token to the client for verification.
  • Token Storage: The client stores the token, usually in a cookie or purpose-marked local storage, and includes it in subsequent requests to the server.
  • User Verification: When the client sends a request to the application server, it verifies the signature in the token and checks the claims in the payload to ensure that the user can access the requested resource.
  • Server Response: If the JWT is valid and the user can access the requested resource.
  • Token Expiration: When the JWT expires, the client must obtain a new JWT by logging in again.

JWT authentication provides several advantages over traditional session-based authentication, including improved scalability and reduced server-side storage requirements. However, it is important to properly secure and manage JWTs to prevent unauthorized access to sensitive information.

What Are the Best Practices for Using JWT Authentication?

Generally speaking, there are best practices for when and when not to use JWT Authentication:

  • When to Use: JWT authentication can be useful in scenarios where the server needs to handle many requests and sessions or in stateless APIs. JWTs can simplify authentication by reducing the number of database calls required for session management and can be passed between microservices to maintain stateless communication.
  • When Not to Use: JWT authentication may not be suitable for applications where the payload contains sensitive information, such as payment details, that must be protected against unauthorized access. JWTs can also pose a security risk if not properly secured, as anyone with access to a valid token can access protected resources. In these scenarios, a session-based authentication mechanism may be more appropriate.

Additionally, there are always implementation best practices when you’ve decided to use the technology, including:

  • Use Strong Encryption: Choose a strong cryptographic signing algorithm, such as, RS256, to sign JWTs. Avoid using insecure algorithms or plaintext.
  • Keep Sensitive Data on the Server: Not include sensitive information in the token payload, such as passwords or credit card numbers. Instead, store this information server-side and retrieve it as needed.
  • Use Short Expiration: Set a short expiration time (around 15-30 minutes) for tokens to reduce the risk of a stolen token being used maliciously..
  • Use Secure HyperText Transfer Protocol (HTTPS): Use HTTPS to encrypt data in transit and prevent man-in-the-middle attacks.
  • Implement Token Revocation: Consider implementing token revocation to invalidate tokens that have been compromised or are no longer needed.

What Are Some Challenges to Avoid When Implementing JWT Authentication?

While there are some significant benefits in implementing JWT authentication, there are always assumptions and pitfalls to avoid. These include:

  • Storing Private Data in the Token: Even with encryption, passing sensitive data across authentication requests is not good practice and can result in compromised accounts.
  • Encryption Failures: Weak algorithms can open the JWT to attacks, such as signature forgery or token tampering. It’s best to use strong cryptographic signing algorithms, such as RS256.
  • Not Validating Tokens: Failing to validate token signatures or expiration times can allow attackers to use stolen or expired tokens to access protected resources.
  • Using Long or No Expiration: While it may be tempting to set long expiration times to reduce the frequency of logins and “improve” user experience, doing so can increase the risk of a stolen token being used maliciously.

Count on Superior authentication with 1Kosmos

A solid cybersecurity defense starts with the perimeter of the outside world, which means strong authentication and identity management. 1Kosmos provides robust multi-factor authentication built on decentralized blockchain technology using intuitive user interfaces that streamline onboarding and adoption.

With 1Kosmos BlockID, you get the following important benefits:

  • Identity-Based Authentication: We push biometrics and authentication into a new “who you are” paradigm. BlockID uses biometrics to identify individuals, not devices, through credential triangulation and identity verification.
  • Cloud-Native Architecture: Flexible and scalable cloud architecture makes it simple to build applications using our standard API and SDK.
  • Identity Proofing: BlockID verifies identity anywhere, anytime and on any device with over 99% accuracy.
  • Privacy by Design: Embedding privacy into the design of our ecosystem is a core principle of 1Kosmos. We protect personally identifiable information in a distributed identity architecture and the encrypted data is only accessible by the user.
  • Private and Permissioned Blockchain: 1Kosmos protects personally identifiable information in a private and permissioned blockchain, encrypts digital identities, and is only accessible by the user. The distributed properties ensure no databases to breach or honeypots for hackers to target.
  • Interoperability: BlockID can readily integrate with existing infrastructure through its 50+ out-of-the-box integrations or via API/SDK.
  • SIM Binding: The BlockID application uses SMS verification, identity proofing, and SIM card authentication to create solid, robust, and secure device authentication from any employee’s phone.

Sign up for our newsletter to learn more about how BlockID can support real security and help mitigate phishing attacks. Also, make sure to read our whitepaper on how to Go Beyond Passwordless Solutions.

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Meet the Author

Robert MacDonald

Vice President of Product Marketing

Robert is the Vice President of Product Marketing at 1Kosmos. He is a highly influential senior global marketer with more than 15 years of marketing experience in B2B and B2C software in the biometric authentication space. Prior to 1Kosmos, Rob managed product strategy and vision for the Identity and Access Management portfolio at Micro Focus, leading a team of product marketers to drive sales and support the channel. Earlier in his career he set the foundation for content planning, sales enablement and GTM activities for ForgeRock. He has also held senior marketing positions at Entrust, Dell, Quest and Corel Corporation.