Example of extracting the payload from a JWS signature

jws-payload-example.ex

jwk_map = %{ "kty" => "oct", "k" => :base64url.encode("secret")}
jws_map = %{ "alg" => "HS256" }
jwt_map = %{ "test" => true }
signature = JOSE.JWT.sign(jwk_map, jws_map, jwt_map)
signature_compacted = JOSE.JWS.compact(signature)

{_, signature_map} = JOSE.JWS.expand(signature_compacted)
payload = JOSE.JWT.from(:base64url.decode(Map.get(signature_map, "payload")))

# one-liner version:

JOSE.JWT.from(:base64url.decode(Map.get(:erlang.element(2, JOSE.JWS.expand(signature_compacted)), "payload")))