Hello there I get that you're new on hive but I feel you have to read the tutorial again for you to have a more better understanding of hive keys.
The memo key is used for encrypting and decrypting messages on hive.
Aside from getting the memo key a little bit wrong, I think you did great. By the way, welcome to Hive Learners. 🙂
RE: (Task) Learning About "Stage-02" The Explanation of Hive Private Keys