User Key Instructions:

1. This "User Key" carries your file upload history (prevents data loss)
2. Copy this "User Key" - when opening this page on other computers, paste it here and click "Use" to automatically retrieve all your previous operation history.


3. Two methods to generate keys:
   1. System auto-generation (use directly as generated)
   2. Customize your preferred "User Key": In the input box, enter your user key (3-30 characters: a-z, A-Z, 0-9, _), then click "Use"
   
   
4. Button functions:
   1. "New_key": Automatically replaces with new user key (new key begins with completely empty data)
   2. "Backup": Automatically downloads key as a txt file to your computer for permanent storage