Secure APIs using JWT(Self Contained) Access Tokens

JSON Web Token (JWT) is an open standard of transmitting information securely between two parties. As the tokens are digitally signed, the information is secured. The authentication and authorization process uses JWT tokens. It is ideal to use JWT tokens as API credentials because JWT tokens can carry claims (data) that are used in order to authenticate and authorize requests.

WSO2 API Manager supports the use of self-contained and signed JWT formatted OAuth2.0 access tokens as API credentials. Therefore, you can use JWT formatted OAuth2.0 access tokens to authenticate any API that is secured using the OAuth2 security scheme. The App Developer can create a JWT or OAuth2.0 application via the Developer Portal, in WSO2 API Manager, in order to subscribe to an API. JWT type applications in WSO2 API Manager uses self-contained signed JWT formatted access tokens.

When an API is invoked using a JWT token, the API Gateway validates the request by itself. In the case of regular opaque access tokens, the API Gateway communicates with the Key Manager (in a distributed deployment) to validate the token.

Prerequisites for JWT based tokens

The following prerequisites have to be satisfied for JWT based tokens to work.

  • Only signed JWT tokens are allowed.

  • The expected token format is as follows:

    base64(header).base64(payload).base64(signature)

  • The public certificate of the private key that is used to sign the tokens should be added to the trust store under the "gateway_certificate_alias" alias. For more information, see Import the public certificate into the client trust store.

    Note

    The latter mentioned prerequisite is not applicable if you use the default certificates, which are the certificates that are shipped with the product itself.

Mandatory attributes of a JWT token

The following are the mandatory attributes that are required for a JWT token.

  • Header
    • typ - The type of the token (JWT).
    • alg - The algorithm used to sign the token (e.g., RS256).
  • Payload
    • sub - The subject of the token, which identifies as to whom the token refers to.
    • application - Application for which the token is generated.
    • consumerKey
    • iat - The time the token was issued.
    • exp - The expiry time of the token.

Using JWT Tokens

Follow the instructions below to work with JWT Authentication in WSO2 API Manager.

Step 1 - Access the Developer Portal

Sign in to the Developer Portal.

https://<hostname>:9443/devportal

Step 2 - Create a JWT token-based application

  1. Click Applications.

  2. Click ADD NEW APPLICATION.

    Add new application option

  3. Enter the application details.

    Let's create an application with the following details.

    FieldValue
    Application NameTestApp
    Per Token Quota10PerMin
    Token TypeJWT
    DescriptionTest App

    Add new Application

Step 3 - Generate a JWT token

  1. Click APIs and click on the PizzaShackAPI.

  2. Click Credentials.

  3. Select the JWT token-based application that you created and select a throttling policy.

  4. Click Subscribe. Subscribe to the API

  5. Click PROD KEYS, which corresponds to the JWT token-based application.

    View list of credentials

  6. Click GENERATE ACCESS TOKEN, click Generate, and copy the JWT access token.

Step 4 - Invoke the API using the JWT token

Invoking an API with a JWT formatted access token is similar to invoking the API with a regular opaque access token. Use the cURL command below to invoke the API via the API Gateway.

curl -k -X GET  "<API_URL>" -H "accept: application/json" -H "Authorization: Bearer <JWT_TOKEN>"
curl -k -X GET "https://localhost:8243/pizzashack/1.0.0/menu" -H "accept: application/json" -H "Authorization: Bearer eyJ0eXAiOiJKV1QiLCJhbGciOiJSUzI1NiIsIng1dCI6IlpqUm1ZVE13TlRKak9XVTVNbUl6TWpnek5ESTNZMkl5TW1JeVkyRXpNamRoWmpWaU1qYzBaZz09In0.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.BBXefDL4DeePYIzBZdZDE_fJDZVza4e0qBU7_Xwrtjut66NKx4xOv8zyjEELudo_q15fpcb0_bwZ4fwRbKECz_TXIH08snivqH0IgDNJDGbEocBbQBj0nQa6eL363lxkDjq-sTrEdKgXjr9rwdEh5SJWE6pkM9rHlLWMFpJKEWOPp726DRqOC60BERvdcHGTN5Bhh029o4eGCFINfzmfpu6bwFqOTIgk9O70WhoYZIi-YiZnG3HHp4kV3T8r3JoW4Ywuy1ANKC3U1cCKHbSS_LmrkM6Z7AR8T_kigCZq0qvMz-8tqEjauUf8avOnpF5GXozDJzU-Y7nwWpmQnIWpwA"
[ 
   { 
      "name":"BBQ Chicken Bacon",
      "description":"Grilled white chicken, hickory-smoked bacon and fresh sliced onions in barbeque sauce",
      "price":"24.99",
      "icon":"/images/6.png"
   },
   { 
      "name":"Chicken Parmesan",
      "description":"Grilled chicken, fresh tomatoes, feta and mozzarella cheese",
      "price":"27.99",
      "icon":"/images/1.png"
   },
   { 
      "name":"Chilly Chicken Cordon Bleu",
      "description":"Spinash Alfredo sauce topped with grilled chicken, ham, onions and mozzarella",
      "price":"13.99",
      "icon":"/images/10.png"
   },
   { 
      "name":"Double Bacon 6Cheese",
      "description":"Hickory-smoked bacon, Julienne cut Canadian bacon, Parmesan, mozzarella, Romano, Asiago and and Fontina cheese",
      "price":"26.99",
      "icon":"/images/9.png"
   },
   { 
      "name":"Garden Fresh",
      "description":"Slices onions and green peppers, gourmet mushrooms, black olives and ripe Roma tomatoes",
      "price":"18.99",
      "icon":"/images/3.png"
   },
   { 
      "name":"Grilled Chicken Club",
      "description":"Grilled white chicken, hickory-smoked bacon and fresh sliced onions topped with Roma tomatoes",
      "price":"11.99",
      "icon":"/images/8.png"
   },
   { 
      "name":"Hawaiian BBQ Chicken",
      "description":"Grilled white chicken, hickory-smoked bacon, barbeque sauce topped with sweet pine-apple",
      "price":"25.99",
      "icon":"/images/7.png"
   },
   { 
      "name":"Spicy Italian",
      "description":"Pepperoni and a double portion of spicy Italian sausage",
      "price":"16.99",
      "icon":"/images/2.png"
   },
   { 
      "name":"Spinach Alfredo",
      "description":"Rich and creamy blend of spinach and garlic Parmesan with Alfredo sauce",
      "price":"22.99",
      "icon":"/images/5.png"
   },
   { 
      "name":"Tuscan Six Cheese",
      "description":"Six cheese blend of mozzarella, Parmesan, Romano, Asiago and Fontina",
      "price":"10.99",
      "icon":"/images/4.png"
   }
]

Additional Information

Validation of API subscriptions

The subscription validation is applied only if the JWT payload contains the subscribedAPIs attribute. The default Key Manager in WSO2 API Manager ensures that this property is added to all the tokens it issues even if the relevant applications have not subscribed to an API. Tokens that are generated before an application subscribes to an API will not contain that API under its subscription details, and will not be allowed to access that specific API. Therefore, JWT tokens should be generated after the application has subscribed to the required API.

Importing the public certificate into the client trust store

Follow the instructions below to import the public certificate into the client trust store.

  1. Navigate to the <API-M_HOME>/repository/resources/security/ directory.

  2. Run the following command to export the public certificate from WSO2 API Manager's key store (wso2carbon.jks). 

    keytool -export -alias wso2carbon -file wso2.crt -keystore wso2carbon.jks

  3. Enter wso2carbon as the default password of the key store when prompted.

  4. Run the following command to import the public certificate into the trust store. 

    keytool -import -trustcacerts -keystore client-truststore.jks -alias gateway_certificate_alias -file wso2.crt
  5. Enter wso2carbon as the default password of the trust store when prompted.

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