US Patent 8020213 Access control method and a system for privacy protection

A method for protecting information in a distributed stream processing system, including: assigning a principal label to a processing component; assigning a first channel label to a first communication channel that is input to the processing component; comparing the principal label to the first channel label to determine if the processing component can read data attributes of the first channel label; and reading the data attributes of the first channel label when the principal label is equal to or has precedence over the first channel label, wherein the principal label includes a read label and a write label and at least one of a selection label, an addition label or a suppression label.