Attack-Tolerant Time-Synchronization in Wireless Sensor Networks

Abstract—Achieving secure time-synchronization in wireless sensor networks (WSNs) is a challenging, but very important problem that has not yet been addressed effectively. This pa-per proposes an Attack-tolerant Time-Synchronization Protocol (ATSP) in which sensor nodes cooperate to safeguard the time-synchronization service against malicious attacks. ATSP exploits the high temporal correlation existing among adjacent nodes in a WSN to achieve (1) adaptive management of the profile of each sensor’s normal behavior, (2) distributed, cooperative detection of falsified clock values advertised by attackers or compromised nodes, and (3) significant improvement of syn-chronization accuracy and stability by effectively compensating the clock drifts with the calibrated clock. To reduce the risk of losing time-synchronization due to attacks on the reference node, ATSP utilizes distributed, mutual synchronization and confines the impact of attacks to a local area (where attacks took place). Furthermore, by maintaining an accurate profile of sensors’ normal synchronization behaviors, ATSP detects various critical attacks while incurring only reasonable communication and computation overheads, making ATSP attack-tolerant and ideal for resource-constrained WSNs. I

Broadcast Authentication for Wireless Sensor Networks Using Nested Hashing and the Chinese Remainder Theorem

Secure broadcasting is an essential feature for critical operations in wireless sensor network (WSNs). However, due to the limited resources of sensor networks, verifying the authenticity for broadcasted messages is a very difficult issue. μTESLA is a broadcast authentication protocol, which uses network-wide loose time synchronization with one-way hashed keys to provide the authenticity verification. However, it suffers from several flaws considering the delay tolerance, and the chain length restriction. In this paper, we propose a protocol which provides broadcast authentication for wireless sensor networks. This protocol uses a nested hash chain of two different hash functions and the Chinese Remainder Theorem (CRT). The two different nested hash functions are employed for the seed updating and the key generation. Each sensor node is challenged independently with a common broadcasting message using the CRT. Our algorithm provides forward and non-restricted key generation, and in addition, no time synchronization is required. Furthermore, receivers can instantly authenticate packets in real time. Moreover, the comprehensive analysis shows that this scheme is efficient and practical, and can achieve better performance than the μTESLA system

Real-time cheat-free gaming on the basis of time-stamp service

A cheat-proof protocol for real-time gaming is proposed under the assumption that time-stamp servers issue serially numbered time stamps honestly and are available near every player, i.e., they exist everywhere in the Internet. With this protocol, each player sends its action to the other player and also sends its hash to the nearest time-stamp server. The time-stamp server sends the signed hash with the time and a serial number back to the player. The actions are checked to verify that they are compatible with the hashes, and the signed hashes are checked to verify that they have the correct time and the serial numbers are contiguous. The only latency in this protocol is the travel time of the packet from one player to another. In comparison with other existing protocols, we confirm that the proposed protocol is as fast as and more secure than the fair synchronization protocol, the fastest existing protoco

Absolute clock synchronization with a single time-correlated photon pair source over 10km

We demonstrate a point-to-point clock synchronization protocol based on bidirectionally propagating photons generated in a single spontaneous parametric down-conversion (SPDC) source. Tight timing correlations between photon pairs are used to determine the single and round-trip times measured by two separate clocks, providing sufficient information for distance-independent absolute synchronization secure against symmetric delay attacks. We show that the coincidence signature useful for determining the round-trip time of a synchronization channel, established using a 10\,km telecommunications fiber, can be derived from photons reflected off the end face of the fiber without additional optics. Our technique allows the synchronization of multiple clocks with a single reference clock co-located with the source, without requiring additional pair sources, in a client-server configuration suitable for synchronizing a network of clocks.Comment: 5 pages, 6 figures. arXiv admin note: text overlap with arXiv:1812.0845

Secure exchange of information by synchronization of neural networks

A connection between the theory of neural networks and cryptography is presented. A new phenomenon, namely synchronization of neural networks is leading to a new method of exchange of secret messages. Numerical simulations show that two artificial networks being trained by Hebbian learning rule on their mutual outputs develop an antiparallel state of their synaptic weights. The synchronized weights are used to construct an ephemeral key exchange protocol for a secure transmission of secret data. It is shown that an opponent who knows the protocol and all details of any transmission of the data has no chance to decrypt the secret message, since tracking the weights is a hard problem compared to synchronization. The complexity of the generation of the secure channel is linear with the size of the network.Comment: 11 pages, 5 figure