JWT Secured Authorization Response Mode (JARM) for OAuth 2.0¶

The JWT Secured Authorization Response Mode for OAuth 2.0 (JARM) specification defines new JWT-based modes to encode OAuth2 authorization responses. These modes allow clients to request authorization response parameters and additional data in the JWT format.

Authorization flow¶

Below is a sample authorization request sent to the authorization endpoint of the WSO2 Identity Server.

https://api.asgardeo.io/t/<organization_name>/oauth2/authorize?
prompt=login
&scope=openid
&redirect_uri=https://<CLIENT_HOST>/redirects/redirect1
&client_id=<CLIENT_ID>
&response_type=<RESPONSE_TYPE>
&response_mode=<RESPONSE_MODE>

The parameters used in the authorization request are defined below.

Parameter	Description
`reponse_type`	Informs Asgardeo of the desired OAuth2 authorization processing flow that will determine the type of authorization information returned. Possible values: `code`: Used for the authorization code flow. `token`: Used for the implicit flow. `code id_token`: Used for the hybrid flow.
`response_mode`	Specifies how the authorization information is returned to the client. By default, the following response modes are supported in Asgardeo: `query` `fragment` `form_post`

JARM response modes¶

Instead of receiving authorization responses in plain text, JARM allows clients to request authorization responses in the JWT format. The specification defines the following response modes, which clients may request using the response_mode parameter.

query.jwt¶

With query.jwt, response parameters are encoded in a single JWT and sent as a query parameter in the redirect URI.

Sample response:

HTTP/1.1 302 Found
Location: https://<CLIENT_HOST>/redirects/redirect1?response=<JWT>

fragment.jwt¶

With fragment.jwt, response parameters are encoded in a single JWT and sent as a fragment parameter in the redirect URI.

Sample response:

HTTP/1.1 302 Found
Location: https://<CLIENT_HOST>/redirects/redirect1#response=<JWT>

form_post.jwt¶

With form_post.jwt, the response parameter containing the JWT is encoded as an HTML form value, which is auto-submitted at the user agent, and thus is transmitted via the HTTP POST method to the client.

Sample response from the authorization server to the user agent:

HTTP/1.1 200 OK
Content-Type: text/html;charset=UTF-8
Cache-Control: no-cache, no-store
Pragma: no-cache

<html>
<head><title>Submit Form</title>
</head>
<body onload="javascript:document.forms[0].submit()">
<form method="post" action="https://<CLIENT_HOST>/redirects/redirect1">
    <input type="hidden" name="response" value=<JWT>/>
</form>
</body>
</html>

The above response results in the following POST request to the client's redirect URI:

POST /redirects/redirect1 HTTP/1.1
Host: <CLIENT_HOST>
Content-Type: application/x-www-form-urlencoded

response=<JWT>

jwt¶

The jwt response mode is a shortcut that indicates the default redirect encoding for the requested response type as follows.

If the response type is code, the default response_mode is query.jwt.
For the response types defined in OIDC (except none), the default response mode is fragment.jwt.
For response types containing token or id_token, the default response mode is fragment.jwt.

Given below is a sample JARM response {JWT}:

eyJ4NXQiOiJNell4TW1Ga09HWXdNV0kwWldObU5EY3hOR1l3WW1NNFpUQTNNV0kyTkRBelpHUXpOR00wWkdSbE5qSmtPREZrWkRSaU9URmtNV0ZoTXpVMlpHVmxOZyIsImtpZCI6Ik16WXhNbUZrT0dZd01XSTBaV05tTkRjeE5HWXdZbU00WlRBM01XSTJOREF6WkdRek5HTTBaR1JsTmpKa09ERmtaRFJpT1RGa01XRmhNelUyWkdWbE5nX1JTMjU2IiwiYWxnIjoiUlMyNTYifQ.ewogICJhdWQiOiAieVQyZkNBaWNRODNRWXltRWpDMGEwZnBqZWM4YSIsCiAgImNvZGUiOiAiNDRjZTU3NTctN2Y1NC0zYjFlLWEzM2YtMThhMzA2MTU1MDUzIiwKICAiaXNzIjogImh0dHBzOi8vYXBpLmFzZ2FyZGVvLmlvL2JpZnJvc3Qvb2F1dGgyL3Rva2VuIiwKICAiZXhwIjogMTY4MDA5MDUwMiwKICAic2Vzc2lvbl9zdGF0ZSI6ICI3ZDg1MjdhNmNmMDU2N2UyNDkxZjE4YmRmZWE2ZTkwYjE0OWZhMjk1MGQ5MmRiYjMxMGI1NDIxOWI3MzNlNDgxLnNwdUVZVUJtUF9FTGVUZEtQX2U3SkEiCn0=.wYIBpEIhYdFq4W3mrx4gcAI2kSgJ5viQ6qGntHsIRMT2wg9F4d-DzMEkMvy4tOup2dlZNby80Sf1djuG44Z-1xbellcuk7hRfotlMOjSLc7fmkzy0b4HvwcN66U9wETWQfixUTbWbOvmqMqzdMQKtSB2b7oWEh5EHOlQQ6vrGJc2eSxquMN_O17PlYKF0smXSgoESIunf8k5sGydO8MvwVZ4-qfqnx7Lx7Huk36CfW-CFI0IXIehi017onOx0FOXwRaizMM45M0zfzyvg4CbZUaGPeGuyO7DVsUPwjdkrjkhiKcXR61S01uqj8-_AAgtZMJHMI3yJQmvWM4ezNe9_Q

Decoded payload:

{
  "aud": "yT2fCAicQ83QYymEjC0a0fpjec8a",
  "code": "44ce5757-7f54-3b1e-a33f-18a306155053",
  "iss": "https://api.asgardeo.io/bifrost/oauth2/token",
  "exp": 1680090502,
  "session_state": "7d8527a6cf0567e2491f18bdfea6e90b149fa2950d92dbb310b54219b733e481.spuEYUBmP_ELeTdKP_e7JA"
}