Multi-Owner Keyword Search over Shared Data without Secure Channels in the Cloud

Searchable encryption allows cloud users to outsource the massive encrypted data to the remote cloud and to search over the data without revealing the sensitive information. Many schemes have been proposed to support the keyword search in a public cloud. However,they have some potential limitations. First,most of the existing schemes only consider the scenario with the single data owner. Second,they need secure channels to guarantee the secure transmission of secret keys from the data owner to data users. Third,in some schemes,the data owner should be online to help data users when data users intend to perform the search,which is inconvenient.In this paper,we propose a novel searchable scheme which supports the multi-owner keyword search without secure channels. More than that,our scheme is a non-interactive solution,in which all the users only need to communicate with the cloud server. Furthermore,the analysis proves that our scheme can guarantee the security even without secure channels. Unlike most existing public key encryption based searchable schemes,we evaluate the performance of our scheme,which shows that our scheme is practical.

Establishment of the Secure Channel between Broker Nodes in Pub/Sub System

The paper mainly discusses the integrity of the forwarded subscription message guaranteed by secure channel which encrypted in data communication by using data encryption standard （DES） algorithm and chaos code algorithm between broker nodes in the routing process of the contentbased publish/subscribe system. It analyzes the security of the secure channel encrypted with data communication by DES algorithm and chaos code algorithm, and finds out the secure channel can be easily attacked by known plain text. Therefore, the paper proposes the improved algorithm of message encryption and authentication, combining encryption and the generation of the message authentication code together to finish scanning at one time, which enhances both the secure degree and running efficiency. This secure channel system has a certain reference value to the pub/sub system requiring highly communication security.

Efficient and Secure Authenticated Quantum Dialogue Protocols over Collective-Noise Channels

Based on the deterministic secure quantum communication, we present a novel quantum dialogue protocol with- out information leakage over the collective noise channel. The logical qubits and four-qubit decoherence-free states are introduced for resisting against collective-dephasing noise, collective-rotation noise and all kinds of unitary collective noise, respectively. Compared with the existing similar protocols, the analyses on security and information-theoretical emciency show that the proposed protocol is more secure and emeient.

A Practical Regular LDPC Coded Scheme for Physical-Layer Information Security

In this paper,we aim to design a practical low complexity low-density parity-check(LDPC)coded scheme to build a secure open channel and protect information from eavesdropping.To this end,we first propose a punctured LDPC coded scheme,where the information bits in a codeword are punctured and only the parity check bits are transmitted to the receiver.We further propose a notion of check node type distribution and derive multi-edge type extrinsic information transfer functions to estimate the security performance,instead of the well-known weak metric bit error rate.We optimize the check node type distribution in terms of the signal-to-noise ratio(SNR)gap and modify the progressive edge growth algorithm to design finite-length codes.Numerical results show that our proposed scheme can achieve a lower computational complexity and a smaller security gap,compared to the existing scrambling and puncturing schemes.

Physical Layer Security in MIMO Wiretap Channels with Antenna Correlation

To investigate the impact of antenna correlation on secrecy performance in MIMO wiretap channels with Nakagami-m fading, the expressions of secrecy outage probability and positive secrecy probability were derived. Diversity order and array gain were also achieved for further insight. The study was based on the information theory that physical layer security can be guaranteed when the quality of the main channel is higher than that of the eavesdropper's channel. Monte Carlo simulations well validated the numerical results of analytic expressions. It was shown that antenna correlation is detrimental to secrecy performance when average SNR of the main channel is at medium and high level. Interestingly, when average SNR of the main channel reduces to low level, the effect of antenna correlation becomes benefi cial to secrecy performance.

The Security Analysis of Two-Step Quantum Direct Communication Protocol in Collective-Rotation Noise Channel

To analyze the security of two-step quantum direct communication protocol （QDCP） by using Einstein-Podolsky Rosen pair proposed by Deng et al. [Phys. Rev. A 68 （2003）042317] in collective-rotation noise channel, an excellent model of noise analysis is proposed. In the security analysis, the method of the entropy theory is introduced, and is compared with QDCP, an error rate point Qo（M ： （Q0, 1.0）） is given. In different noise levels, if Eve wants to obtain the same amount of information, the error rate Q is distinguishable. The larger the noise level ~ is, the larger the error rate Q is. When the noise level ~ is lower than 11%, the high error rate is 0.153 without eavesdropping. Lastly, the security of the proposed protocol is discussed. It turns out that the quantum channel will be safe when Q 〈 0.153. Similarly, if error rate Q〉 0.153 = Q0, eavesdropping information I 〉 1, which means that there exist eavesdroppers in the quantum channel, and the quantum channel will not be safe anymore.

Security Simulation of Continuous-Variable Quantum Key Distribution over Air-to-Water Channel Using Monte Carlo Method

Considering the ocean water＇s optical attenuation and the roughness of the sea surface, we analyze the security of continuous-variable （CV） quantum key distribution （QKD） based Mr-to-water channel. The effects of the absorp- tion and scattering on the transmittance of underwater quantum channel and the maximum secure transmission distance are studied. Considering the roughness of the sea surface, we simulate the performance bounds of CV QKD with different wind speeds using the Monte Carlo method. The results show that even if the secret key rate gradually reduces as the wind speed increases, the maximum transmission distance will not be affected obviously. Compared to the works regarding short-distance underwater optical communication, our research represents a significant step towards establishing secure communication between air platform and submarine vehicle.

Secure Transmission Scheme for Parallel Relay Channels Based on Polar Coding

This paper considers the use of polar codes to enable secure transmission over parallel relay channels.By exploiting the properties of polar codes over parallel channels, a polar encoding algorithm is designed based on Channel State Information（CSI） between the legitimate transmitter（Alice） and the legitimate receiver（Bob）.Different from existing secure transmission schemes, the proposed scheme does not require CSI between Alice and the eavesdropper（Eve）. The proposed scheme is proven to be reliable and shown to be capable of transmitting information securely under Amplify-and-Forward（AF） relay protocol, thereby providing security against passive and active attackers.

Using IND-CVA for constructing secure communication

Within the framework of UC （universally composable） security, a general method is presented to construct a secure channel protocol with using IND-CVA （indistinguishability of encryption scheme under ciphertext verification attacks）. A channel protocol with using the method first invokes an ideal keyexchange protocol to get a session key, and then computes the messages with an authenticated encryption scheme. The paper shows that a channel protocol is UC secure if and only if the underlying authenticated encryption scheme is both IND-CVA secure and INT-PTXT secure. The condition about secure channel protocol in this paper is much weaker than IND-CCA secure and INT-CTXT secure. The IND-CVA can be presented for describing the privacy requirements of secure channels in detail. Moreover, the method for designing secure channel protocol in the paper reduces the UC security of secure channels, which are measured by action-simulation in the UC security framework, to the security of authenticated encryption schemes, which are measured semantically.