Youku Tudou sent a short message verification code. How can we be sure it's from official website?

First, see if the sender of the short message has VI certification marks, such as "enterprise logo" and "enterprise name", which can only be revealed after the enterprise certification.

Second, check whether there is a service button under the message, and you can query "business card" and "service hotline". These are also very reliable official messages, and messages sent by pseudo base stations cannot present this interface.