A public operator processes data streams from multiple operators in different streaming applications to reduce resource costs and increase efficiency in a streaming system. The public operator uses tuple level security with a unique key for each streaming application to securely process the data streams. A stream security module (SSM) manages encryption to and from the public operators to insure other streaming applications with access to the shared public operator don't have access to data of other applications that may belong to other customers or users. The stream security module may be incorporated into the streams manager of a streaming system.