def validation_keys_hash(client_id = nil, client_secret = nil)
    hdrs = client_id && client_secret ?
        { "authorization" => Http.basic_auth(client_id, client_secret)} : {}
    response = json_get(target, "/token_keys", key_style, hdrs)

    keys_map = {}

    response['keys'].each do |key|
      keys_map[key['kid']] = key
    end

    keys_map
  end
def validation_keys_hash(client_id = nil, client_secret = nil)
    hdrs = client_id && client_secret ?
        { "authorization" => Http.basic_auth(client_id, client_secret)} : {}
    response = json_get(target, "/token_keys", key_style, hdrs)

    keys_map = {}

    response['keys'].each do |key|
      keys_map[key['kid']] = key
    end

    keys_map
  end
Gets all currently valid token verification keys. If the server has had
 its signing key changed, then +/token_key+ will return a verification key
 that does not match a JWT token issued before the change. To validate the
 signature of these tokens, refer to the +kid+ header of the JWT token. The
 +validation_keys_hash+ method returns a hash of all currently valid
 verification keys, indexed by +kid+. To retrieve symmetric keys as part of
 the result, client credentials are required.
 @param (see Misc.server)
 @return [Hash]