Abstract: An interdiction system includes software agents masquerading as nodes in a decentralized network, a query matcher that receives search results captured by the software agents and reports matches with protected files back to the software agents, and a central coordinating authority that coordinates activities of the software agents by sending instructions to the software agents specifying actions to be taken. Possible activities and related interdicting methods include manipulating search results before forwarding them on in the network, quarantining selected nodes in the network, performing file impersonations such as transferring synthesized decoys, performing file transfer attenuation, and hash spoofing.