: It likely uses AES-256 encryption if the creator enabled security, which is a standard feature of the 7z format. Requirements for Extraction

: You need all subsequent volumes (e.g., QXJmc2FY.7z.002 , QXJmc2FY.7z.003 ) in the same folder . If any part is missing, the archive cannot be reconstructed.

: You must always right-click and "Extract" the .001 file specifically; the software will automatically find and join the other numbered parts. Safety Warning

: It is a "spanned" or "split" archive. The .001 extension indicates this is the first piece of a larger file that was divided into smaller segments to make it easier to transfer or store.