The Canvas team often fields questions about how to store sensitive files in a Canvas course. Maybe you have an answer key that you will share with students once they complete an assessment but you don't want that answer key to circulate among all students in the course.
Canvas is not an ideal platform for hosting sensitive files. By default, course files are visible and accessible to all users, so placing restrictions on files plays against Canvas's nature. Combine that with a feature that is often misunderstood (Only Available with Link), and you can easily expose files to students unintentionally. Below are gotchas around restricting files and folders to students in Canvas and recommendations for regulating access to sensitive files.
Only Available with Link
You can place a restriction on a file so that it is only available to students who have the link. This only works in a very narrow context: the actual Files tab in your Canvas course. There, students will not be able to search or browse for the file in the Files interface.
Gotcha
Some instructors mistakenly believe you need to deliberately issue the link to a student. However, if you link to the file in an assignment or module, students will be able to access the file with no restrictions.
Schedule Availability
You can configure a file to be available only between specified dates. Outside the availability dates, such files will not be findable by students in course Files. If linked from an assignment or module, the student will see the name of the file but will not be able to open it outside the availability window.
Gotcha
When importing content from one term to the next, availability dates will not update to the new timeline, even if you select "Adjust events and due dates" when you import content. You will need to manually update the availability window on files.
Recommendations
The best advice for restricting file access to a subset of students in Canvas is to set the file to Only Available with Link so it won't be findable in the Files tab. Place the file in a new assignment, then use the Assign To area to designate which students or sections have access to the assignment.
Outside Canvas, consider Google Drive if you wish to share and collaborate, or Box Secure Storage if it is highly sensitive or private data.
About the Files Tab
In usability testing, students report that the Files tab is very confusing, particularly if instructors direct students to use the Files tab to find documents. Consider hiding the Files tab. Hiding the Files tab means students will not see it in their course navigation, nor can they reach it by guessing the URL. Hiding the Files tab also means you don't need to set restrictions on specific files. Link to files, documents, and PDFs within Modules or Pages to make it easy for students to find the material you want them to engage with.