Quantum Cryptography, or more accurately Quantum Key Distribution (QKD), is an unconditionally secure key growing technique based on the principles of quantum mechanics. It is unconditionally secure because no quantum state can be copied or measured without disturbing it. However, the practical implementation of QKD protocols requires an immutable public channel. In case the public channel is n...

The pilot spoofing attack is considered as an active eavesdropping activity launched by an adversary during the reverse channel training phase. By transmitting the same pilot signal as the legitimate user, the pilot spoofing attack is able to degrade the quality of legitimate transmission and, more severely, facilitate eavesdropping. In an effort to detect the pilot spoofing attack and minimize...

Quantum key distribution (QKD) provides means for unconditional secure key transmission between two distant parties. However, in practical implementations, it suffers from quantum hacking due to device imperfections. Here we propose a hybrid measurement attack, with only linear optics, homodyne detection, and single photon detection, to the widely used vacuum + weak decoy state QKD system when ...

An important area in computer and communications security research is to make various pioneering ideas practical. In this paper we develop a new cryptographic key distribution system based on the uncertainty principle in quantum physics. The new system employs a novel technique that mixes two quantum states in the transmission of photonic signals. On one hand, this technique forces an eavesdrop...

This is a study of the security of the Coherent One-Way (COW) protocol for quantum cryptography, proposed recently as a simple and fast experimental scheme. In the zero-error regime, the eavesdropper Eve can only take advantage of the losses in the transmission. We consider new attacks, based on unambiguous state discrimination, which perform better than the basic beam-splitting attack, but whi...

Computational based cryptography might not guarantee long term security if computational algorithms, computers, and so on are made remarkable progress. Therefore, quantum cryptography with unconditionally security attracts attention. In this paper, we consider security of a two-way quantum key distribution protocol, so called Ping-Pong protocol. As a result, we introduce not only robustness but...

Cryptography has traditionally been used for defensive purposes. Ciphers defend against a passive eavesdropper. Public key infrastructures defend against an active adversary that mounts a man-in-the-middle attack. Digital signature algorithms defend against a forger. Ecash systems defend against a counterfeiter and a double-spender. Pseudorandom bit generators defend against a next-bit predicto...

We consider a generalisation of Ekert’s entanglement-based quantum cryptographic protocol where qubits are replaced by quN its (i.e., N -dimensional systems). In order to study its robustness against optimal incoherent attacks, we derive the information gained by a potential eavesdropper during a cloning-based individual attack. In doing so, we generalize Cerf’s formalism for cloning machines a...

The website fingerprinting attack aims to identify the content (i.e., a webpage accessed by a client) of encrypted and anonymized connections by observing patterns of data flows such as packet size and direction. This attack can be performed by a local passive eavesdropper – one of the weakest adversaries in the attacker model of anonymization networks such as Tor. In this paper, we present a n...

Secured communications in the presence of eavesdropper node is grave for the successful operations in the wireless relay networks. In the proposed work, choose two hop wireless relay networks to enhance security against the eavesdropper node. This paper considers four node networks, they are one source, and three decode and forward relay, one destination and one eavesdropper node. To transmit t...