JWT

python3

JSON Web Tokens (JWT) are a compact, URL-safe way of representing claims between two parties. They are commonly used for securely transmitting information as a JSON object, which can be verified and trusted because it is digitally signed. JWTs consist of three parts: the header, the payload, and the signature.

In this tool, you can encode or decode JWTs. Encoding is used to create a new JWT with your payload and secret key, while decoding is used to extract and read the information from an existing JWT.

Key Features:

• Encode: Converts your payload and secret key into a JWT.
• Decode: Extracts the header, payload, and signature from a JWT.
• Command Output: Provides a Python command for encoding or decoding the JWT, which you can run directly from your terminal.
• Interactive: The form updates in real-time as you enter data, showing the corresponding Python command and result.

How JWT Encoding and Decoding Works:

• Encoding: To encode a JWT, you provide a JSON payload and a secret key. The resulting JWT will consist of three parts:
  1. Header (specifies the algorithm used for signing)
  2. Payload (the claims you want to encode)
  3. Signature (signed using the secret key)
• Decoding: To decode a JWT, you provide the encoded token (a string with three parts separated by dots). You can optionally provide the secret key to verify the signature during decoding.

Common JWT Encoding and Decoding Options:

• Encode: Converts your payload and secret into a JWT.
• Decode: Extracts and decodes the contents of a JWT. The secret key is optional and only required if you want to verify the token’s signature.

Example Commands

Encoding Example:

Input Payload (JSON format):

{
  "user": "alice",
  "role": "admin",
  "iat": 1645327890
}

Secret Key:

mysecretkey123

Command:

> python3 -c "import jwt; print(jwt.encode({'user': 'alice', 'role': 'admin', 'iat': 1645327890}, 'mysecretkey123', algorithm='HS256'))"

Output JWT (Generated JWT):

eyJhbGciOiAiSFMyNTYiLCAidHlwIjogIkpXVCJ9.eyJ1c2VyIjogImFsaWNlIiwgInJvbGUiOiAiYWRtaW4iLCAiaWF0IjogMTY0NTMyNzg5MH0.xCZ3h7Y1eHV1oAl1w38YotQsTkMIxYWrfp77iqErA3Y

Decoding Example:

Input JWT (Encoded JWT):

eyJhbGciOiAiSFMyNTYiLCAidHlwIjogIkpXVCJ9.eyJ1c2VyIjogImFsaWNlIiwgInJvbGUiOiAiYWRtaW4iLCAiaWF0IjogMTY0NTMyNzg5MH0.xCZ3h7Y1eHV1oAl1w38YotQsTkMIxYWrfp77iqErA3Y

Secret Key (Optional for verification):

mysecretkey123

Command:

> python3 -c "import jwt; print(jwt.decode('eyJhbGciOiAiSFMyNTYi...==', 'mysecretkey123', algorithms=['HS256']))"

Decoded Result:

{
  "user": "alice",
  "role": "admin",
  "iat": 1645327890
}

Where to Find JWTs:

JWTs are typically issued by authentication systems or APIs. Here are a few common places where you might encounter or generate JWTs:

• Authentication Systems: JWTs are commonly used for secure user authentication in web applications (e.g., as part of an OAuth2 flow).
• APIs: Many APIs use JWTs to authenticate requests, particularly for stateless authentication.
• JWT Libraries: You can generate JWTs using libraries in various programming languages (e.g., Python’s pyjwt library, Node.js’s jsonwebtoken package).

Understanding JWTs:

A JWT is composed of three parts:

1. Header: Contains metadata about the token, including the signing algorithm (e.g., HS256).
2. Payload: The data you want to store (e.g., user ID, roles, or permissions). This is a base64-encoded JSON object.
3. Signature: A cryptographic signature created using the header and payload, ensuring that the token hasn’t been tampered with.

Result Output:

You can see the result of the encoding or decoding process directly in the output section. It will also generate the corresponding Python command, which you can use for further operations or save for your reference.