A method for securely broadcasting information to a group of undisclosed recipients. The information in an information system is encoded by applying a hash function to a group of messages to form the information stream, wherein portions of the information in the information stream are intended for respective ones of the group of undisclosed recipients. The information is encoded such that that only an intended recipient can decode a portion of the information intended for the intended recipient. The information stream is broadcasted to the group of undisclosed recipients.