JWK set settings for an OAuth / OIDC client

Preface

In order to verify a signature of request objects coming from a client, or to provide encrypted ID tokens to a client, you have to register the client’s public key to Authlete for signature verification and/or message encryption.

This article explains how to register a JWK set to settings of an OAuth / OIDC client that is registered to an Authlete service.

Preparing a JWK set

Instruction in this section is for illustrative purposes. Do not apply the following JWK set to your production environment.

An administrator of the OAuth / OIDC client is to prepare a JWK set including a public key. Note that the key set must not include a private key.

The following example illustrates usage of mkjwk.org service to generate a key pair for encryption, and parameters specified for it.

Item	Value
Key Type	EC (Elliptic Curve)
Curve	P-256
Key Use	Encryption
Algorithm	(none)
Key ID	SHA-256

By clicking “Generate” button, the tool shows the generated keys in various formats. We will use “Public and Private Keypair Set” in this example.

The original JWK set is as follows.

{
    "keys": [
        {
            "kty": "EC",
            "d": "4AEnTq3H8gcIutIoJCCZuv9GgWdKRaoJIXQkdM8r0UA",
            "use": "enc",
            "crv": "P-256",
            "kid": "_agec7UaYVN4c3RZQJQhUuR6nFSnqEXywv3QaIfFRFk",
            "x": "ilLNQ-Lcp_t5DBs9puJVI3JhwqlMndTILjkBrNd3Dsc",
            "y": "3Uy7NIHilkOWviGXMRIl2ZUE4L7Mc8ub4VhosE3l8t8"
        }
    ]
}

Remove a private key below.

"d": "4AEnTq3H8gcIutIoJCCZuv9GgWdKRaoJIXQkdM8r0UA",

The result is as follows.

{
    "keys": [
        {
            "kty": "EC",
            "use": "enc",
            "crv": "P-256",
            "kid": "_agec7UaYVN4c3RZQJQhUuR6nFSnqEXywv3QaIfFRFk",
            "x": "ilLNQ-Lcp_t5DBs9puJVI3JhwqlMndTILjkBrNd3Dsc",
            "y": "3Uy7NIHilkOWviGXMRIl2ZUE4L7Mc8ub4VhosE3l8t8"
        }
    ]
}

This JSON document is to be used as a JWK set of the client’s public key.

Registering a JWK set

Register the public key JWK set to the settings of the OAuth / OIDC client.

In Developer Console, add the JWK set to “JWK Set Content” under “JWK Set” tab for the client.

Now the JWK set has been registered for the OAuth / OIDC client.