Krita does not access, collect, use, share or transmit any personal information or user data whatsoever. Since we don’t have access to any of your data, sensitive or otherwise, we don’t sell it, of course.
Unless you enable the newsfeed, Krita does not make any network connections. The newsfeed is retrieved over an https connection.
You can configure Krita to save author information in images you create, but Krita does not do that by default.