[keycloak-user] Where do I find the secret to verify a token

Dear List Members, I am working on implementing a Single Sign On with keycloak and I have implemented the Standard Flow, I can exchange the Authorization Grant to receive the tokens, but I cannot find a way to verify them. Each time I try to check the token, classical tools like jwt.io or https://www.jsonwebtoken.io/ says the signature is incorrect. I would like to know, which secret does Keycloak use to sign (with HS256) the tokens ? And where can I find it ? I tried the client secret, but it seems wrong to me. Many thanks for your help, Cheers, Bruno Mairlot