Method, system, network and computer program product for securing administrative transactions over a network

Communication between an administrator device and an administered device in a network is arranged in the form of a chain of digitally signed communication items including messages sent from an originator device to a recipient device. Each message has an associated respective digitally signed receipt, and the originator device is configured not to send a new item toward the recipient device in the absence of a respective digitally signed receipt for a previously sent item. With at least one, and preferably by both of the administrator device and the administered device, there is stored a history record of communication items exchanged therebetween. The history record is agreed upon and signed by both the administrator device and the administered device.