# File lib/openid/consumer.rb, line 452
    def begin(service)
      nonce = self.create_nonce
      token = self.gen_token(service.consumer_id, service.server_id,
                             service.server_url)

      assoc = self.get_association(service.server_url)
      return SuccessRequest.new(assoc, token, nonce, service)
    end