Biblio

Physical-layer key (PLK) generation scheme is a new key generation scheme based on wireless channel reciprocity. However, the security of physical layer keys still lacks sufficient theoretical support in the presence of eavesdropping attacks until now, which affects the promotion in practical applications. By analyzing the propagation mode of multipath signals under non-line-of-sight (nLoS), an improved spatial cross-correlation model is constructed, where the spatial cross-correlation is between eavesdropping channel and legitimate channel. Results show that compared with the multipath and obstacle distribution of the channel, the azimuth and distance between the eavesdropper and the eavesdropped user have a greater impact on the cross-correlation.

Underwater Acoustic Sensor Networks (UASNs) are often deployed in hostile environments, and they face many security threats. Moreover, due to the harsh characteristics of the underwater environment, UASNs are vulnerable to malicious attacks. One of the most dangerous security threats is the eavesdropping attack, where an adversary silently collects the information exchanged between the sensor nodes. Although careful assignment of transmission power levels and optimization of data flow paths help alleviate the extent of eavesdropping attacks, the network lifetime can be negatively affected since routing could be established using sub-optimal paths in terms of energy efficiency. In this work, two optimization models are proposed where the first model minimizes the potential eavesdropping risks in the network while the second model maximizes the network lifetime under a certain level of an eavesdropping risk. The results show that network lifetimes obtained when the eavesdropping risks are minimized significantly shorter than the network lifetimes obtained without considering any eavesdropping risks. Furthermore, as the countermeasures against the eavesdropping risks are relaxed, UASN lifetime is shown to be prolonged, significantly.

A new quantum secret sharing protocol based on the ping-pong protocol of quantum secure direct communication is proposed. The pairs of entangled qutrits are used in protocol, which allows an increase in the information capacity compared with protocols based on entangled qubits. The detection of channel eavesdropping used in the protocol is being implemented in random moments of time, thereby it is possible do not use the significant amount of quantum memory. The security of the proposed protocol to attacks is considered. A method for additional amplification of the security to an eavesdropping attack in communication channels for the developed protocol is proposed.

In recent years, secret key generation based on physical layer security has gradually attracted high attentions. The wireless channel reciprocity and eavesdropping attack are critical problems in secret key generation studies. In this paper, we carry out a simulation and experimental study of channel reciprocity in terms of measuring channel state information (CSI) in both time division duplexing (TDD) and frequency division duplexing (FDD) modes. In simulation study, a close eavesdropping wiretap channel model is introduced to evaluate the security of the CSI by using Pearson correlation coefficient. In experimental study, an indoor wireless CSI measurement system is built with N210 and X310 universal software radio peripheral (USRP) platforms. In TDD mode, theoretical analysis and most of experimental results show that the closer eavesdropping distance, the higher CSI correlation coefficient between eavesdropping channel and legitimate channel. However, in actual environment, when eavesdropping distance is too close (less than 1/4 wavelength), this CSI correlation seriously dropped. In FDD mode, both theoretical analysis and experimental results show that the wireless channel still owns some reciprocity. When frequency interval increases, the FDD channel reciprocity in actual environment is better than that in theoretical analysis.

Applying security to the transmitted image is very important issues, because the transmission channel is open and can be compromised by attackers. To secure this channel from the eavesdropping attack, man in the middle attack, and so on. A new hybrid encryption image mechanism that utilize triangular scrambling, DNA encoding and chaotic map is implemented. The scheme takes a master key with a length of 320 bit, and produces a group of sub-keys with two length (32 and 128 bit) to encrypt the blocks of images, then a new triangular scrambling method is used to increase the security of the image. Many experiments are implemented using several different images. The analysis results for these experiments show that the security obtained on by using the proposed method is very suitable for securing the transmitted images. The current work has been compared with other works and the result of comparison shows that the current work is very strong against attacks.

File encryption is an effective way for an enterprise to prevent its data from being lost. However, the data may still be deliberately or inadvertently leaked out by the insiders or customers. When the sensitive data are leaked, it often results in huge monetary damages and credit loss. In this paper, we propose a novel group file encryption/decryption method, named the Group File Encryption Method using Dynamic System Environment Key (GEMS for short), which provides users with auto crypt, authentication, authorization, and auditing security schemes by utilizing a group key and a system environment key. In the GEMS, the important parameters are hidden and stored in different devices to avoid them from being cracked easily. Besides, it can resist known-key and eavesdropping attacks to achieve a very high security level, which is practically useful in securing an enterprise's and a government's private data.