Information Leakage Problem Research Articles

Multi-Party Quantum Private Comparison Protocol Based on Entanglement Swapping of Bell Entangled States**Supported by the National Natural Science Foundation of China under Grant No. 61402407

Recently, Liu et al. proposed a two-party quantum private comparison (QPC) protocol using entanglement swapping of Bell entangled state (Commun. Theor. Phys. 57 (2012) 583). Subsequently Liu et al. pointed out that in Liu et al.'s protocol, the TP can extract the two users' secret inputs without being detected by launching the Bell-basis measurement attack, and suggested the corresponding improvement to mend this loophole (Commun. Theor. Phys. 62 (2014) 210). In this paper, we first point out the information leakage problem toward TP existing in both of the above two protocols, and then suggest the corresponding improvement by using the one-way hash function to encrypt the two users' secret inputs. We further put forward the three-party QPC protocol also based on entanglement swapping of Bell entangled state, and then validate its output correctness and its security in detail. Finally, we generalize the three-party QPC protocol into the multi-party case, which can accomplish arbitrary pair's comparison of equality among K users within one execution.

Information Leakage Problem in High-Capacity Quantum Secure Communication with Authentication Using Einstein—Podolsky—Rosen Pairs**Supported by the National Natural Science Foundation of China under Grant Nos 61502101 and 61170321, the Natural Science Foundation of Jiangsu Province under Grant No BK20140651, and Funded by PAPD and CICAEET.

The information leakage problem often exists in bidirectional quantum secure direct communication or quantum dialogue. In this work, we find that this problem also exists in the one-way quantum secure communication protocol [Chin. Phys. Lett. 32 (2015) 050301]. Specifically the first bit of every four-bit message block is leaked out without awareness. A way to improve the information leakage problem is given.

Information Leakage Problem in Efficient Bidirectional Quantum Secure Direct Communication with Single Photons in Both Polarization and Spatial-Mode Degrees of Freedom

The information leakage problem in the efficient bidirectional quantum secure direct communication protocol with single photons in both polarization and spatial-mode degrees of freedom is pointed out. Next, a way to revise this protocol to a truly secure one is given. We hope people pay more attention to the information leakage problem in order to design truly secure quantum communication protocols.

Decoy-state quantum key distribution with a leaky source

In recent years, there has been a great effort to prove the security of quantum key distribution (QKD) with a minimum number of assumptions. Besides its intrinsic theoretical interest, this would allow for larger tolerance against device imperfections in the actual implementations. However, even in this device-independent scenario, one assumption seems unavoidable, that is, the presence of a protected space devoid of any unwanted information leakage in which the legitimate parties can privately generate, process and store their classical data. In this paper we relax this unrealistic and hardly feasible assumption and introduce a general formalism to tackle the information leakage problem in most of existing QKD systems. More specifically, we prove the security of optical QKD systems using phase and intensity modulators in their transmitters, which leak the setting information in an arbitrary manner. We apply our security proof to cases of practical interest and show key rates similar to those obtained in a perfectly shielded environment. Our work constitutes a fundamental step forward in guaranteeing implementation security of quantum communication systems.

Quantum dialogue protocols over collective noise using entanglement of GHZ state

In this paper, two quantum dialogue (QD) protocols based on the entanglement of GHZ states are proposed to resist the collective noise. Besides, two new coding functions are designed for each of the proposed protocols, which can resist two types of collective noise: collective-dephasing noise and collective-rotation noise, respectively. Furthermore, it is also argued that these QD protocols are also free from the Trojan horse attacks and the information leakage problem.

A network based document management model to prevent data extrusion

This paper presents a network-based document management model to protect sensitive data from unauthorized disclosure in organizations. The presented framework utilizes XML security concept, PKI cryptosystem and an XML-based metadata embedding approach mainly to address the problem of information leakage that may happen through employees of a company (also known as the insider threat).By utilizing the above-mentioned techniques, our suggested framework wraps the confidential documents with an additional layer of security meta-data that can be investigated in critical network points of an organization to prevent illegal data distribution. This solution can also guarantee data confidentiality, integrity, and support for non-repudiation. We believe our suggested model can effectively prevent intentional or unintentional data leak incidents.

Two-party quantum key agreement based on four-particle GHZ states

Based on four-particle GHZ states, the double CNOT operation and the delayed measurement technique, a two-party quantum key agreement (QKA) protocols is proposed. The double CNOT operation makes each four-particle GHZ state collapse into two independent quantum states without any entanglement. Furthermore, one party can directly know the two quantum states and the other party can be aware of the two quantum states by using the corresponding measurement. According to the initial states of the two quantum states, two parties can extract the secret keys of each other by using the publicly announced value or by performing the delayed measurement, respectively. Then the protocol achieves the fair establishment of a shared key. The security analysis shows that the new protocol can resist against participant attacks, the Trojan horse attacks and other outsider attacks. Furthermore, the new protocol also has no information leakage problem and has high qubit efficiency.

Practical Security Bounds Against the Trojan-Horse Attack in Quantum Key Distribution

In the quantum version of a Trojan-horse attack, photons are injected into the optical modules of a quantum key distribution system in an attempt to read information direct from the encoding devices. To stop the Trojan photons, the use of passive optical components has been suggested. However, to date, there is no quantitative bound that specifies such components in relation to the security of the system. Here, we turn the Trojan-horse attack into an information leakage problem. This allows us quantify the system security and relate it to the specification of the optical elements. The analysis is supported by the experimental characterization, within the operation regime, of reflectivity and transmission of the optical components most relevant to security.

Fault-tolerant authenticated quantum dialogue using logical Bell states

Two fault tolerant authenticated quantum dialogue (AQD) protocols are proposed in this paper by employing logical Bell states as the quantum resource, which combat the collective-dephasing noise and the collective-rotation noise, respectively. The two proposed protocols each can accomplish the mutual identity authentication and the dialogue between two participants simultaneously and securely over one kind of collective noise channels. In each of two proposed protocols, the information transmitted through the classical channel is assumed to be eavesdroppable and modifiable. The key for choosing the measurement bases of sample logical qubits is pre-shared privately between two participants. The Bell state measurements rather than the four-qubit joint measurements are adopted for decoding. The two participants share the initial states of message logical Bell states with resort to the direct transmission of auxiliary logical Bell states so that the information leakage problem is avoided. The impersonation attack, the man-in-the-middle attack, the modification attack and the Trojan horse attacks from Eve all are detectable.

Fault-Tolerant Quantum Dialogue Without Information Leakage Based on Entanglement Swapping between Two Logical Bell States* *Supported by the National Natural Science Foundation of China under Grant Nos. 61402407 and 11375152

At present, the anti-noise property and the information leakage resistant property are two great concerns for quantum dialogue (QD). In this paper, two anti-noise QD protocols without information leakage are presented by using the entanglement swapping technology for two logical Bell states. One works well over a collective-dephasing noise channel, while the other takes effect over a collective-rotation noise channel. The negative influence of noise is erased by using logical Bell states as the traveling quantum states. The problem of information leakage is avoided by swapping entanglement between two logical Bell states. In addition, only Bell state measurements are used for decoding, rather than four-qubit joint measurements.

Robust quantum dialogue based on a shared auxiliary logical Bell state against collective noise

In this paper, two robust quantum dialogue (QD) protocols against collective-dephasing noise and collective-rotation noise are presented, respectively. In each of the proposed QD protocols, four logical Bell states, each of which is made up of four physical qubits, are used to combat collective noise. The information leakage problem is overcome by directly transmitting the auxiliary logical Bell states in two steps from one communication party to the other. For decoding, Bell state measurements rather than four-qubit joint measurements are used. The effectiveness against an eavesdroppers active attacks such as the intercept-resend attack, the measure-resend attack, the entangle-measure attack and the Trojan horse attack can be guaranteed.

Robust quantum dialogue based on the entanglement swapping between any two logical Bell states and the shared auxiliary logical Bell state

In this paper, using the quantum entanglement swapping technologies under the collective-dephasing noise and the collective-rotation noise, two robust quantum dialogue protocols are proposed, respectively. The logical Bell states are used as the traveling states to combat the collective noise. The auxiliary logical Bell state is shared privately between two participants through the manner of direct transmission first. After encoded with the receiver's secret messages, it swaps entanglement with its adjacent logical Bell state. In this way, the information leakage problem is avoided. Moreover, Eve's active attacks can be detected with the help of decoy photon technology. For decoding, the Bell state measurements rather than the four-qubit joint measurements are needed.

Quantum secure direct dialogue over collective noise channels based on logical Bell states

A scheme for quantum secure direct dialogue protocols, which is adapted to both collective-dephasing noise and collective-rotation noise, is proposed in this paper by using the logical Bell states as the traveling states to resist collective noise. All logical Bell states are used to transmit secret messages from either of two participants except those used for security checks. Each of the logical Bell states used for transmitting secret messages can carry two classical bits. Bell state measurements rather than four-qubit joint measurements are used for decoding. The two participants can accomplish the direct dialogue without any additional classical communication for decoding. The information leakage problem is avoided with resort to the two-step transmission, the ping-pong transmission and the absence of classical communication for the encoded quantum states. The two participants can speak to each other either simultaneously or sequentially. Furthermore, the two participants can transmit secret messages of different lengths to each other in one round communication. The proposed scheme is so flexible that it is much alike the practical conversation in real life.

A Kind of Quantum Dialogue Protocols Without Information Leakage Assisted by Auxiliary Quantum Operation

In this paper, a kind of quantum dialogue (QD) protocols without information leakage assisted by quantum operation is proposed. The participant in charge of preparation can automatically know the collapsed states after quantum operation performed on the prepared quantum states. The other participant is able to know the collapsed states derived from the prepared quantum states through quantum measurement. The information leakage problem is avoided by means of imposing auxiliary quantum operation on the prepared quantum states.

COVARIANCE ASSISTED SCREENING AND ESTIMATION.

Consider a linear model Y = X β + z, where X = Xn,p and z ~ N(0, In ). The vector β is unknown and it is of interest to separate its nonzero coordinates from the zero ones (i.e., variable selection). Motivated by examples in long-memory time series (Fan and Yao, 2003) and the change-point problem (Bhattacharya, 1994), we are primarily interested in the case where the Gram matrix G = X'X is non-sparse but sparsifiable by a finite order linear filter. We focus on the regime where signals are both rare and weak so that successful variable selection is very challenging but is still possible. We approach this problem by a new procedure called the Covariance Assisted Screening and Estimation (CASE). CASE first uses a linear filtering to reduce the original setting to a new regression model where the corresponding Gram (covariance) matrix is sparse. The new covariance matrix induces a sparse graph, which guides us to conduct multivariate screening without visiting all the submodels. By interacting with the signal sparsity, the graph enables us to decompose the original problem into many separated small-size subproblems (if only we know where they are!). Linear filtering also induces a so-called problem of information leakage, which can be overcome by the newly introduced patching technique. Together, these give rise to CASE, which is a two-stage Screen and Clean (Fan and Song, 2010; Wasserman and Roeder, 2009) procedure, where we first identify candidates of these submodels by patching and screening, and then re-examine each candidate to remove false positives. For any procedure β̂ for variable selection, we measure the performance by the minimax Hamming distance between the sign vectors of β̂ and β. We show that in a broad class of situations where the Gram matrix is non-sparse but sparsifiable, CASE achieves the optimal rate of convergence. The results are successfully applied to long-memory time series and the change-point model.

Multi-document threshold signcryption scheme

Without proper and well-managed encryption, digital communications interception is technically easy to tap over public networks, and it causes unauthorized disclosure of sensitive information and irreparable harm to individuals as well as organizations. To ensure that digital information remains complete, accessible and secure at all times, it needs to be reliably processed on security measures at both the sending and receiving ends. Signcryption like other aspects of a cryptographic system simultaneously provides the characteristics of both digital signature and encryption and can fulfill the basic security requirements of information confidentiality, integrity and availability in transmission. In this paper, we introduce a threshold signcryption scheme based on elliptic curve cryptography to combine the dynamic knapsack cryptosystem technique with the Chinese remainder theorem and achieve a more robust security cryptosystem for multi-document transmission. With the proposed composition scheme of threshold signcryption function, participants not only can employ the avalanche effect of unsystematic properties founded on the elliptic curve cryptography's point addition to chaotically generate pre-shared secure cipher keys against the counterfeiting or potential information leakage problems but also apply the advantages of a smaller key size and its high strength of security under the elliptic curve discrete logarithm problem assumption to carry out digital communications, which can be fast and reliably transmitted over a public channel. Copyright © 2014 John Wiley & Sons, Ltd.

Fragmentation in Presence of Data Dependencies

Fragmentation has been recently proposed as a promising approach to protect the confidentiality of sensitive associations whenever data need to undergo external release or storage. By splitting attributes among different fragments, fragmentation guarantees confidentiality of the associations among these attributes under the assumption that such associations cannot be reconstructed by re-combining the fragments. We note that the requirement that fragments do not have attributes in common, imposed by previous proposals, is only a necessary, but not sufficient, condition to ensure that information in different fragments cannot be recombined as dependencies may exist among data enabling some form of linkability. In this paper, we identify the problem of improper information leakage due to data dependencies, provide a formulation of the problem based on a natural graphical modeling, and present an approach to tackle it in an efficient and scalable way.

Information leakage resistant quantum dialogue against collective noise

In this paper, two information leakage resistant quantum dialogue (QD) protocols over a collective-noise channel are proposed. Decoherence-free subspace (DFS) is used to erase the influence from two kinds of collective noise, i.e., collective-dephasing noise and collective-rotation noise, where each logical qubit is composed of two physical qubits and free from noise. In each of the two proposed protocols, the secret messages are encoded on the initial logical qubits via two composite unitary operations. Moreover, the single-photon measurements rather than the Bell-state measurements or the more complicated measurements are needed for decoding, making the two proposed protocols easier to implement. The initial state of each logical qubit is privately shared between the two authenticated users through the direct transmission of its auxiliary counterpart. Consequently, the information leakage problem is avoided in the two proposed protocols. Moreover, the detailed security analysis also shows that Eve's several famous active attacks can be effectively overcome, such as the Trojan horse attack, the intercept-resend attack, the measure-resend attack, the entangle-measure attack and the correlation-elicitation (CE) attack.

Quantum Secure Dialogue with Quantum Encryption

How to solve the information leakage problem has become the research focus of quantum dialogue. In this paper, in order to overcome the information leakage problem in quantum dialogue, a novel approach for sharing the initial quantum state privately between communicators, i.e., quantum encryption sharing, is proposed by utilizing the idea of quantum encryption. The proposed protocol uses EPR pairs as the private quantum key to encrypt and decrypt the traveling photons, which can be repeatedly used after rotation. Due to quantum encryption sharing, the public announcement on the state of the initial quantum state is omitted, thus the information leakage problem is overcome. The information-theoretical efficiency of the proposed protocol is nearly 100%, much higher than previous information leakage resistant quantum dialogue protocols. Moreover, the proposed protocol only needs single-photon measurements and nearly uses single photons as quantum resource so that it is convenient to implement in practice.

Efficient public verification proof of retrievability scheme in cloud

Cloud storage is an important service of cloud computing. After data file is outsourced, data owner no longer physical controls over the storage. To efficiently verify these data integrity, several Proof of Retrievability (POR) schemes were proposed to achieve data integrity checking. The existing POR schemes offer decent solutions to address various practical issues, however, they either have a non-trivial (linear or quadratic) communication cost, or only support private verification. And most of the existing POR schemes exist active attack and information leakage problem in the data checking procedure. It remains open to design a secure POR scheme with both public verifiability and constant communication cost. To solve the above problems , we propose a novel preserving-private POR scheme with public verifiability and constant communication cost based on end-to-end aggregation authentication in this paper. To resist information leakage, we include zero-knowledge technique to hide the data in the integrity checking process. Our scheme is shown to be secure and efficient by security analysis and performance analysis. The security of our scheme is related to the Computational Diffie---Helleman Problem and Discrete logarithm problem. Finally, we also extend the POR scheme to support multi-file integrity checking and simulation results show that the verifier only needs less computational cost to achieve data integrity checking in our extended scheme.