Deterministic and Efficient Three-Party Quantum Key Distribution

Quantum information processing is based on the laws of quantum physics and guarantees the unconditional security. In this thesis we propose an efficient and deterministic three-party quantum key distribution algorithm to establish a secret key between two users. Using the formal methodological approach, we study and model a quantum algorithm to distribute a secret key to a sender and a receiver when they only share entanglement with a trusted party but not with each other. It distributes a secret key by special pure quantum states using the remote state preparation and controlled gates. In addition, we employ the parity bit of the entangled pairs and ancillary states to help in preparing and measuring the secret states. Distributing a state to two users requires two maximally entangled pairs as the quantum channel and a two-particle von Neumann projective measurement. This protocol is exact and deterministic. It distributes a secret key of d qubits by 2d entangled pairs and on average d bits of classical communication. We show the security of this protocol against the entanglement attack and offer a method for privacy amplification. Moreover, we also study the problem of distributing Einstein-Podolsky-Rosen (EPR) in a metropolitan network. The EPR is the building block of entanglement-based and entanglement-assisted quantum communication protocols. Therefore, prior shared EPR pair and an authenticated classical channel allow two distant users to share a secret key. To build a network architecture where a centralized EPR source creates entangled states by the process of spontaneous parametric down-conversion (SPDC) then routes the states to users in different access networks. We propose and simulate a metropolitan optical network (MON) architecture for entanglement distribution in a typical telecommunication infrastructure. The architecture allows simultaneous transmission of classical and quantum signals in the network and offers a dynamic routing mechanism to serve the entire metropolitan optical network

Deterministic And Efficient Three-party Quantum Key Distribution

The field of quantum computing is based on the laws of quantum mechanics, including states superposition and entanglement. Quantum cryptography is amongst the most surprising applications of quantum mechanics in quantum information processing. Remote state preparation allows a known state to a sender to be remotely prepared at a receiver’s location when they prior share entanglement and transmit one classical bit. A trusted authority in a network where every user is only authenticated to the third party distributes a secret key using quantum entanglement parity bit, controlled gates, ancillary states, and transmit one classical bit. We also show it is possible to distribute entanglement in a typical telecom metropolitan optical network

Quantum Mutual Authentication Scheme Based on Bell State Measurement

Authentication is one of the security services that ensure sufficient security of the system by identification and verification. Also, it assures the identity of the communicating party to be that the claimed one. To build a quantum channel between two unauthenticated to each other users, a trusted authority is needed to create a mutual authentication with each party before they communicate. Using Bell measurement and entanglement swapping, we present a protocol that mutually authenticates the identity of the sender and the receiver then, constructs a quantum channel based on Bell basis. The sender and the receiver use the quantum channel to communicate using entanglement-assisted quantum communication protocols. Additionally, the protocol renews the shared secret key between the trusted authority and each user after authentication process. The protocol provides the necessary authentication and key distribution to create a quantum channel between the sender and receiver

Entanglement Distribution and Secret Key Sharing In Optical Networks

Communicating a quantum state remotely is possible by Remote State Preparation. Sender Alice create a pure state known to her and help the receiver Bob to securely prepare the state remotely instead of sending the physical quantum state. To successfully perform this protocol the sender and the receiver must share Einstein-Podolsky-Rosen (EPR) state and have access to an authenticated classical channel. The sender and the receiver must be sharing an entangled bit for each state the sender wishes to prepare at the receiver’s location. In this paper we introduce a protocol to create and distribute the required entangled pairs between the communicating parities. A trusted source of EPR states will provide the necessary entangled states required to the sender and the receiver. The distributed EPR state will be used between the communicating parties to create secret keys by using remote state preparation protocol. The proposed protocol will provide unconditional security and any attacking attempt will be discovered due to the disturbance in the states

Performance Evaluation of AODV and DSR Routing Protocols in MANET Networks

Extensive use of wireless networks in different fields increases the need to improve their performance, as well as minimize the amplitude of loss messages. Device mobility, where there is no standard topology that can be applied or fixed routing that can be designed, is a topic that received recent attention in wireless networks. In a Mobile Ad Hoc Network (MANET), some nodes may join the network while others may leave. In this paper, we analyze a MANET’s performance for two proactive protocols; Ad Hoc On-Demand Distance Vector (AODV) Protocol, and Dynamic Source Routing (DSR) Protocol. By using network simulator NS2, we setup and evaluate the performance of AODV and DSR protocols with respect to the packets’size

Quantum mutual authentication scheme based on Bell state measurement

Authentication is one of the security services that ensures sufficient security of the system by identification and verification. Also, it assures the identity of the communicating party to be that the claimed one. To build a quantum channel between two unauthenticated to each other parties, first, a trusted authority is needed to establish a mutual authentication with each party. Using Bell measurement and entanglement swapping, we present a protocol that mutually authenticates the identity of the sender and the receiver, then constructs a quantum channel based on Bell basis. After, the sender and the receiver use the quantum channel to communicate using entanglement-assisted quantum communication protocols. Additionally, the protocol renews the shared secret key between the trusted authority and each user after each authentication process. The protocol provides the necessary authentication and key distribution to create a quantum channel between the sender and receiver

Entanglement-based quantum digital signatures over deployed campus network

The quantum digital signature protocol offers a replacement for most aspects of public-key digital signatures ubiquitous in today's digital world. A major advantage of a quantum digital signatures protocol is that it can have information-theoretic security, whereas public-key cryptography cannot. Here we demonstrate and characterize hardware to implement entanglement-based quantum digital signatures over our campus network. Over 25 hours, we collect measurements on our campus network, where we measure sufficiently low quantum bit error rates (<5\% in most cases) which in principle enable quantum digital signatures over up to 50 km as shown in rigorous simulation accompanied by a noise model developed specifically for our implementation. These results show quantum digital signatures can be successfully employed over deployed fiber. While the current implementation of our entanglement-based approach has a low signature rate, feasible upgrades would significantly increase the signature rate. In addition, our reported method provides great flexibility in the number of users.Comment: 16 pages, 5 figures, 1 tabl

Continuous-variable quantum key distribution field-test with true local oscillator

Continuous-variable quantum key distribution (CV-QKD) using a true local (located at the receiver) oscillator (LO) has been proposed to remove any possibility of side-channel attacks associated with transmission of the LO as well as reduce the cross-pulse contamination. Here we report an implementation of true LO CV-QKD using "off-the-shelf" components and conduct QKD experiments using the fiber optical network at Oak Ridge National Laboratory. A phase reference and quantum signal are time multiplexed and then wavelength division multiplexed with the classical communications which "coexist" with each other on a single optical network fiber. This is the first demonstration of CV-QKD with a receiver-based true LO over a deployed fiber network, a crucial step for its application in real-world situations

Two-mode squeezing over deployed fiber coexisting with conventional communications

Squeezed light is a crucial resource for continuous-variable (CV) quantum information science. Distributed multi-mode squeezing is critical for enabling CV quantum networks and distributed quantum sensing. To date, multi-mode squeezing measured by homodyne detection has been limited to single-room experiments without coexisting classical signals, i.e., on ``dark'' fiber. Here, after distribution through separate fiber spools (5~km), $-0.9\pm0.1$-dB coexistent two-mode squeezing is measured. Moreover, after distribution through separate deployed campus fibers (about 250~m and 1.2~km), $-0.5\pm0.1$-dB coexistent two-mode squeezing is measured. Prior to distribution, the squeezed modes are each frequency multiplexed with several classical signals -- including the local oscillator and conventional network signals -- demonstrating that the squeezed modes do not need dedicated dark fiber. After distribution, joint two-mode squeezing is measured and recorded for post-processing using triggered homodyne detection in separate locations. This demonstration enables future applications in quantum networks and quantum sensing that rely on distributed multi-mode squeezing.Comment: 23 pages, 13 figures, 2 table

Generation and characterization of ultrabroadband polarization-frequency hyperentangled photons

We generate ultrabroadband photon pairs entangled in both polarization and frequency bins through an all-waveguided Sagnac source covering the entire optical C- and L-bands (1530--1625 nm). We perform comprehensive characterization of high-fidelity states in multiple dense wavelength-division multiplexed channels, achieving full tomography of effective four-qubit systems. Additionally, leveraging the inherent high dimensionality of frequency encoding and our electro-optic measurement approach, we demonstrate the scalability of our system to higher dimensions, reconstructing states in a 36-dimensional Hilbert space consisting of two polarization qubits and two frequency-bin qutrits. Our findings hold potential significance for quantum networking, particularly dense coding and entanglement distillation in wavelength-multiplexed quantum networks