Control of messages in publish/subscribe system

A method carried out at a broker system in a publish/subscribe architecture, the broker system configured to allow a separate publishing system of the publish/subscribe architecture to maintain fine-grain control of a message throughout the entire publish/subscribe architecture including through end use of the message by a plurality of subscribing systems, the method comprising:

• receiving, from the publishing system, the message for publishing to the plurality of subscribing systems, the message as received by the broker system including associated metadata, the associated metadata incorporating at least a broker-system-layer-control metadata subset designed to control delivery of the message by the broker system and a subscribing-system-layer-control metadata subset designed to control use of the message by the subscribing systems, wherein both metadata subsets are selected by a publishing user corresponding with the publishing system such that the entirety of the associated metadata defines the fine-grain control of the message in the form of restrictions on the message to be applied differentially at multiple layers of the publish/subscribe architecture as well as differentially among the plurality of subscribing systems;
• determining, by the broker system and based on an analysis of the broker-system-layer-control metadata subset, that restrictions on the delivery of the message to each of the subscribing systems varies based on characteristics of the subscribing systems;
• looking up, by the broker system and based on the determination about the broker-system-layer-control metadata subset, the characteristics of each subscribing system;
• applying, by the broker system and based on the looked-up information for each subscribing system, the required restrictions to the delivery of the message to each subscribing system differentially such that the fine-grain control of the message by the publishing system is maintained at the broker-system layer of the publish/subscribe architecture;
• and
• forwarding, by the broker system, at least the subscribing-system-layer-control metadata subset to each subscribing system to whom the message is delivered,
• wherein, based on its analysis of the subscribing-system-layer control metadata subset, each subscribing system differently applies restrictions on the use of the message by its corresponding subscribing user, wherein the restrictions applied by each subscribing system are in addition to the restrictions applied by the broker system such that the fine-control of the message by the publishing system is also maintained at the subscribing-system-layer of the publish/subscribe architecture.