We present a secure communication protocol which allows direct secure communication. Using quantum nonlocality, information is transferred in a deterministic manner. The security of this protocol is based on the ‘High fidelity implies low entropy’. In fact, the eavesdropper-Eve can use a denial-of-service (DoS) attack to destroy a quantum communication,e.g., she can destroy the travel photon to...

A general study of arbitrary finite-size coherent attacks against continuous-variable quantum cryptographic schemes is presented. It is shown that, if the size of the blocks that can be coherently attacked by an eavesdropper is fixed and much smaller than the key size, then the optimal attack for a given signal-to-noise ratio in the transmission line is an individual Gaussian attack. Consequent...

We present strong attacks against quantum key distribution schemes which use quantum memories and quantum gates to attack directly the final key. We analyze a specific attack of this type, for which we find the density matrices available to the eavesdropper and the optimal information which can be extracted from them. We prove security against this attack and discuss security against any attack...

This paper presents a multi-stage, multi-photon quantum key distribution protocol based on the double-lock cryptography. It exploits the asymmetry in the detection strategies between the legitimate users and the eavesdropper. The security analysis of the protocol is presented with coherent states under the interceptresend attack, the photon number splitting attack, and the man-in-the-middle att...

Wireless Sensor Network (WSN) is a broad network consisting of a number of sensor nodes in it. WSN is used mainly for monitoring and data aggregation purpose. A best plan of opponent may attack the sink node which is the aggregation point for the whole network. So, first there comes a need to secure the sink node from adversary. There are previous work are done by providing location privacy to ...

This note describes some cryptographic issues related to multi‐located parties. In general, multi‐located parties make it difficult for the eavesdropper to mount the man‐in‐the‐ middle attack. Conversely, they make it easier to address problems such as joint encryption and error correction coding. It is easier to implement the three‐stage quantum cryptography protocol.

TheMySQL challenge–and–response authentication protocol is proved insecure. We show how can an eavesdropper impersonate a valid user after witnessing only a few executions of this protocol. The algorithm of the underlying attack is presented. Finally we comment about implementations and statistical results.

In 1974, Ralph Merkle proposed the first unclassified scheme for secure communications over insecure channels. When legitimate communicating parties are willing to spend an amount of computational effort proportional to some parameter N , an eavesdropper cannot break into their communication without spending a time proportional to N, which is quadratically more than the legitimate effort. We sh...

In this paper, we propose a novel two-party semiquantum key distribution (SQKD) protocol by only employing one kind of GHZ-like state. The proposed SQKD can create private shared between quantum party with unlimited abilities and classical limited without the existence third party. doesn't need Hadamard gate or entanglement swapping. Detailed security analysis turns out that resist various famo...

Quantum key distribution can be performed with practical signal sources such as weak coherent pulses. One example of such a scheme is the Bennett–Brassard protocol that can be implemented via polarization of the signals, or equivalent signals. It turns out that the most powerful tool at the disposition of an eavesdropper is the photon-number splitting attack. We show that this attack can be ext...