Based on EPR pairs, this paper proposes a different quantum private comparison (QPC) protocol enabling two parties to compare the equality of their information without revealing the information content. Due to the use of quantum entanglement of Bell state as well as one-way quantum transmission, the new protocol provides easier implementation as well as better qubit efficiency (near 50%) than the other QPCs. It is secure against Trojan horse attack and other well-known attacks.

New quantum private comparison protocol using EPR pairs

Fragile image watermarking with pixel-wise recovery based on overlapping embedding strategy

Quantum communications promise to revolutionise the way information is exchanged and protected. Unlike their classical counterpart, they are based on dim optical pulses that cannot be amplified by conventional optical repeaters. Consequently they are heavily impaired by propagation channel losses, which confine their transmission rate and range below a theoretical limit known as repeaterless secret key capacity. Overcoming this limit with today's technology was believed to be impossible until the recent proposal of a scheme that uses phase-coherent optical signals and an auxiliary measuring station to distribute quantum information. Here we experimentally demonstrate such a scheme for the first time and over significant channel losses, in excess of 90 dB. In the high loss regime, the resulting secure key rate exceeds the repeaterless secret key capacity, a result never achieved before. This represents a major step in promoting quantum communications as a dependable resource in today's world.

Experimental quantum key distribution beyond the repeaterless secret key capacity

This paper proposes a novel watermarking scheme with flexible self-recovery quality. The embedded watermark data for content recovery are calculated from the original discrete cosine transform (DCT) coefficients of host image and do not contain any additional redundancy. When a part of a watermarked image is tampered, the watermark data in the area without any modification still can be extracted. If the amount of extracted data is large, we can reconstruct the original coefficients in the tampered area according to the constraints given by the extracted data. Otherwise, we may employ a compressive sensing technique to retrieve the coefficients by exploiting the sparseness in the DCT domain. This way, all the extracted watermark data contribute to the content recovery. The smaller the tampered area, the more available watermark data will result in a better quality of recovered content. It is also shown that the proposed scheme outperforms previous techniques in general.

Watermarking With Flexible Self-Recovery Quality Based on Compressive Sensing and Compositive Reconstruction

Securing internet of medical things systems: Limitations, issues and recommendations

This study presents the first authenticated semi-quantum key distribution (ASQKD) protocols without using authenticated classical channels By pre-sharing a master secret key between two communicants, a sender with advanced quantum devices can transmit a working key to a receiver, who can merely perform classical operations The idea of ASQKD enables establishment of a key hierarchy in security systems that also eases the key management problem The proposed protocols are free from several well-known attacks

Authenticated semi-quantum key distribution protocol using Bell states

Recover the tampered image based on VQ indexing

This work proposes two fault tolerant quantum secure direct communication (QSDC) protocols which are robust against two kinds of collective noises: the collective-dephasing noises and the collective-rotation noises, respectively. The two QSDC protocols are constructed from four-qubit DF states which consist of two logical qubits. The receiver simply performs two Bell state measurements (rather than four-qubit joint measurements) to obtain the secret message. The protocols have qubit efficiency twice that of the other corresponding fault tolerant QSDC protocols. Furthermore, the proposed protocols are free from Trojan horse attacks.

Fault tolerant two-step quantum secure direct communication protocol against collective noises

This work proposes two quantum dialogue protocols, each of which is robust against one of the following two kinds of collective noise: collective-dephasing noise and collective-rotation noise. Both quantum dialogue protocols are constructed from four-qubit DF states that consist of two Bell states. The receiver simply performs two Bell state measurements to obtain the secret message. Moreover, the proposed protocols are free from information leakage because some shared private quantum states are established in the new protocols to allow the legitimate users to exchange their secret messages securely.

Quantum dialogue protocols immune to collective noise

This work proposes a new dynamic quantum secret sharing (DQSS) protocol using the measurement property of Greenberger---Horne---Zeilinger state and the controlled-NOT gate. In the proposed DQSS protocol, an agent can obtain a shadow of the secret key by simply performing a measurement on single photons. In comparison with the existing DQSS protocols, it provides better qubit efficiency and has an easy way to add a new agent. The proposed protocol is also free from the eavesdropping attack, the collusion attack, and can have an honesty check on a revoked agent.

Chun-Wei Yang

Papers

Authenticated semi-quantum key distribution protocol using Bell states

Recover the tampered image based on VQ indexing

Fault tolerant two-step quantum secure direct communication protocol against collective noises

Quantum dialogue protocols immune to collective noise

Dynamic quantum secret sharing protocol based on GHZ state