If you want to grade assignments without knowing who submitted them, you can hide student names in Grading Tool .
Click the Grading Tool link .
Click the Settings link next to the Wrench icon to open Grading Tool Options.
Click the checkbox next to Hide student names in the Grading Tool to hide the student names.
Click the Save Settings button.
View the student drop-down menu and verify that all student names are hidden. You can also hide student names in the Gradebook.