In today's cloud-native world, the risk of compromised secrets is ever-present, amplified by longer exposure times and the complexity of manual key rotation. Traditional secrets management solutions often involve cumbersome redistribution processes, which can introduce human error and pose significant challenges for developers.

To address these issues, let's dive into the powerful world of JSON Web Tokens (JWTs).

This article will focus on how short-lived JWTs can revolutionize JavaScript authentication workflows. We’ll see how JWTs simplify the complexities of securing API endpoints, making authentication smarter and more secure. As a cybersecurity secret weapon, JWTs are essential for protecting sensitive data in modern cloud-native environments.

JWTs provide an efficient, flexible, and cost-effective solution, balancing security and scalability. From session management to API protection, JWTs are a game-changer in today's fast-evolving security landscape.

Join me to discover how JWTs are transforming security paradigms and reshaping JavaScript authentication into a powerful defense strategy for today’s digital ecosystem.

Logo of JSON Web Tokens — jwt.io

JSON WEB TOKENS BASICS

JSON Web Tokens (JWT) are compact, URL-safe tokens used for securely transmitting information between parties as a JSON object. They are commonly used for authentication and information exchange.

The token is mainly composed of 3 parts: header, payload, signature.

These three parts are separated by dots(.).

FORMAT: [header].[payload].[signature]

HEADER : A simple header of a JWT looks like the code below:

Source: https://jwt.io/

JWT HEADER serves as a container for critical metadata about the token.

• 1. Among the metadata is the type of token, which in this case is “JWT,” indicating that it is a JSON Web Token.
• 2. Another crucial element found within the Header is the cryptographic algorithm used to create and verify the token’s integrity. HS256 and RS256 are the two main algorithms we make use of in the header section of a JWT. Some JWT’s can also be created without a signature or encryption. Such a token is referred to as unsecured and its header should have the value of the alg object key assigned to as ‘none’.

JWT PAYLOAD:

• 1. The payload is the part of the JWT where all the user data is added. This data is also referred to as the ‘claims’ of the JWT. This information is readable by anyone, so it is always advised to not put any confidential information in here. This part generally contains user information.
• 2. There are three types of claims: registered, public, and private claims.
• a. Registered claims: These are a set of predefined claims which are not mandatory but recommended, to provide a set of useful, interoperable claims. Some of them are: iss (issuer), exp (expiration time), sub (subject), aud (audience), and others. Note: claim name is only 3 letters this makes jwt compact.
• b. Private claims: These are the custom claims created to share information between parties that agree on using them and are neither registered or public claims. (email, name, address)
• c. Public Claims: They can be defined at will by those using JWTs. However, to prevent namespace collisions, any new Claim Name should either be registered in the IANA "JSON Web Token Claims" registry or be a Public Name: a value that contains a Collision-Resistant Name.

Sample JWT:

In the above payload:

• 1. “subject” (“sub”) claim represents the subject of the token, typically the unique identifier of the user or entity associated with the token.
• 2. “expiration time” (“exp”) claim, defining the point in time after which the token becomes invalid. This feature aids in enhancing security, preventing the misuse of expired tokens.
• 3. "iat" (issued at) claim identifies the time at which the JWT was issued. This claim can be used to determine the age of the JWT.
• 4. iss “issuer” claim, which identifies the entity that issued the token. This claim can be used to verify the token’s legitimacy, ensuring it was indeed generated by a trusted authority.
• 5. aud "audience claim": Recipient for which the JWT is intended. The audience value is either the application (Client ID) for an ID Token or the API that is being called (API Identifier) for an Access Token.
• 6. Name, email id is some of the custom/private claims.
• 7. We can put as many claims as we want inside a payload, though unlike header, no claims are mandatory in a payload.

Some registered claims: https://auth0.com/docs/secure/tokens/json-web-tokens/json-web-token-claims#registered-claims

JWT SIGNATURE

• 1. It used to validate that the token is trustworthy and has not been tampered with.
• 2. It is used to verify that the sender of the JWT is who it says it is and...