Creation of JWT

import jwt

import datetime

SECREAT_KEY="your_secreat_key"

def create_jwt():

  payload = {

               "sub": "arpita@gmail.com",

               "exp" : datetime.datetime.utcnow() + datetime.timedelta(minutes=30),

                "iat" : datetime.datetime.utcnow(),

         }

        token=jwt.encode(payload, SECRET_KEY,  algorithm="HS256")

        return token

jwt_token = create_jwt()

print("generated JWT:",jwt_token)

1. Import library

• jwt: It is the PyJWT library used to create and verify JSON Web Tokens.

• datetime: Used to set the expiration time (exp) and issued-at time (iat) for the token.

2. Define secret key

• This is the secret key used to sign and verify the token.

• Keep this key private, as it is needed to verify the token's authenticity.

3. Create jwt Function

• Defines a function create_jwt() that creates and returns a JWT token.

4. Set payload

• The payload contains important user information:

• "sub": Stores the subject (usually user email or user ID).

• "exp": Expiration time (30 minutes from now). After this time, the token will be invalid.

• "iat": Issued at (current time) when the token is generated.

5. Encode the token

• jwt.encode() generates a JWT by encrypting the payload with:

  1. Secret key (SECRET_KEY) → used for security.

  2. Algorithm ("HS256") → a hashing method to ensure security.

  The result is a signed, secure token.

6. Return token

• The function returns the generated token.

7. Generate and Print the Token

• Calls the create_jwt() function to generate a JWT.

• Prints the JWT string, which can be sent to users for authentication.

Verification of JWT

def verify_jwt(token):

  try:

        decoded_payload= jwt.decode(token,SECRET_KEY,algorithms=["HS256"]

         print("Decoded payload:" , decoded_payload)

   except jwt.ExpiredSignatureError:

         print("Token has expired.")

  except jwt.InvalidTokenError:

         print("Invalid token.")

verify_jwt(jwt_token)

1.function to verify JWT

• defining the function and it takes jwt token as input and varify it

2. Try to decode the token

• jwt.decode: this is for decode the token

• token : the jwt token for verified

• SECRETS_KEY: is used for encoding

• algorithm=["HS256"]:hashing algorithm used for verification

• if decode is successfully then it extract the user data and prints it

3. Handle expired token error

• if token has expired then expiredsignitureerror is raised and prints token has expired.

4. Handle invalid token error

• if token is incorrect then invalidtokenerror is raised and prints invalid token

5. call the varification function

• passing jwt token generated earlier ,and decode the token check the validity