# Custom authorization server - change signing algorithm?

**URL:** <https://devforum.okta.com/t/custom-authorization-server-change-signing-algorithm/26898>\
**Category:** OAuth/OIDC\
**Created:** [February 19, 2024, 8:48pm UTC](https://devforum.okta.com/t/custom-authorization-server-change-signing-algorithm/26898 "2024-02-19T20:48:27Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![snappydresser](https://avatars.discourse-cdn.com/v4/letter/s/9de053/32.png) [@snappydresser](https://devforum.okta.com/u/snappydresser)\
**Post date:** [February 19, 2024, 8:48pm UTC](https://devforum.okta.com/t/custom-authorization-server-change-signing-algorithm/26898/1 "2024-02-19T20:48:27Z")

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I’ve successfully created a custom authorization server. When I go to the keys endpoint `https://dev-1234.okta.com/oauth2/foobat/v1/keys` there is a single key with `alg` set to `RS256`. When I do an OIDC authorization code auth flow I get a JWT token signed using `RS256`.

How can I instead configure the custom authorization server to issue tokens signed using `ES256`? I prefer `ES256` as they are faster to verify. Thank you.

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**Author:** ![vk-giri](https://sea1.discourse-cdn.com/oktadev/user_avatar/devforum.okta.com/vk-giri/32/5178_2.png) [@vk-giri](https://devforum.okta.com/u/vk-giri)\
**Post date:** [February 26, 2024, 6:40am UTC](https://devforum.okta.com/t/custom-authorization-server-change-signing-algorithm/26898/2 "2024-02-26T06:40:46Z")

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You can use the [Client Credentials Flow](https://developer.okta.com/docs/guides/implement-grant-type/clientcreds/main/) to generate tokens signed using ES256.

This example might be an help - [Build a JWT for Client Authentication | Okta Developer](https://developer.okta.com/docs/guides/build-self-signed-jwt/java/main/#build-a-jwt-with-a-private-key)

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**Author:** ![system](https://global.discourse-cdn.com/oktadev/original/1X/589c4c5f80de422d01f47cee7185a7fb8227835c.png) [@system](https://devforum.okta.com/u/system)\
**Post date:** [March 27, 2024, 6:41am UTC](https://devforum.okta.com/t/custom-authorization-server-change-signing-algorithm/26898/3 "2024-03-27T06:41:20Z")

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