Box, Inc. is a public company based in Redwood City, California. It develops a set of cloud services for individuals and businesses. Piktures is NOT associated with Box.
Piktures is able to manage, view, download from, and upload photos to Box.
Piktures uses Box WebDav access to execute those operations. As a Piktures user, you will have to enter your username and password. The credentials will be stored locally on your smartphone. They are not sent anywhere outside of this device.