Yes!
The privacy settings for a bucket may be modified under the Display section under Bucket Settings. This is illustrated below:

A private bucket is only accessible to collaborators i.e. users that have permission to access your bucket. These permissions are of two types namely:

• Editor - Read/write permissions on the bucket i.e. allows a user to add drops and change the settings for the bucket
• Viewer - The user can only view the bucket; they cannot add/remove drops or change the bucket settings

A public bucket on the other hand is accessible to all the registered users on the deployment. However, for cases where the deployment's administrator has enabled anonymous access, the bucket is accessible to both registered and non-registered (anonymous) users.

NOTE: This information (on making buckets private/public) also applies to rivers.