Improvements to publish-subscribe protocols are provided, including a method for communicating data in a network comprising publisher devices, a broker and subscriber devices, comprising one of the publisher devices: i-a. receiving a public key from the broker; i-b. determining, based on one or more attributes of data to be published to the broker, whether a sensitivity level of the data is low; and ii. following completion of both of steps i-a and i-b, publishing the data to the broker, wherein: when step i-b results in a determination that the sensitivity level of the data is low, step ii comprises transmitting the data to the broker unencrypted; and when step i-b results in a determination that the sensitivity level of the data is not low, step ii comprises encrypting the data then transmitting resulting encrypted data to the broker, wherein the step of encrypting the data uses the public key.