Pecan: A circuit-less P2P design for anonymity

We propose Pecan, a circuit-less, peer-to-peer low-latency anonymous system. In Pecan, users do not need to construct a circuit for communications. The anonymity is provided by Pecan´s highly peer-to-peer, circuit-less structure and the feature that all re-encryption keys are generated locally by the intermediate nodes themselves. Pecan also has stronger resistance against several DoS attacks that the circuit-based systems do not. The high anonymity is obtained without harming user experience: a user could send anonymous requests and get corresponding responses with less stringent requirements on the intermediate nodes involved on the route. Pecan´s design is based on a revised onion routing and a new proxy re-encryption algorithm. These cryptographic algorithms maintain a small amount of processing overhead for system nodes. Our analysis and experiment showed the total processing delay is relatively small in comparison to the whole end-to-end latency. The throughput is satisfactory for normal users´ online activities.