What would be the private and public key to validate JIra access token ?

[Nikhil Dhiman]

I am working on a requirement where we are going to use OAuth 2.0(3LO) flow for authentication purpose with one of our applications. I was successfully able to generate Access token by going through the steps mentioned here:  here: https://developer.atlassian.com/cloud/confluence/oauth-2-3lo-apps/

I want to validate above generated access token in backend application and to do the same we need a private and public key(or IssuerSigningKey key). I am not sure where i can find the same?

Thanks much in advance !