Someone added my qq and asked me for my password, but I blacklisted him and deleted him. Then he added me, and I didn't agree, but he appeared on the list of strangers again.

Want a password? Then you should quickly change a difficult password, preferably a combination of letters, numbers and symbols. Then you open the QQ security center, set up secret protection questions, bind mobile phones, etc. In order to improve security. It's best to set all three secrets, as long as you remember the topic yourself. This is very useful. After setting it up, your QQ will be difficult to be stolen. If you blacklist him, don't delete him. Stay on the blacklist so that you can't see him even if he talks to you.