code: def decrypt(self, token, signature=None):
          
          binary = rsa.decrypt(token, self.my_privkey)
          if signature:
              rsa.verify(binary, signature, self.his_pubkey)
          return binary
docs: Decrypt binary data.
  
          **中文文档**
  
          - 接收消息时只需要自己的privkey
          - 如需使用签名, 则双方都需要持有对方的pubkey