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To solve the problem of lack of trust in cloud platforms, we propose an image encryption algorithm based on the Lattice Hash function and privacy protection in this paper. A new chaotic system using Tent Map and Sine Map is designed in our proposed scheme, which does not have a period window. Meanwhile, our algorithm uses a new chaos system to provide random matrices F for Lattice Hash functions. The image feature vector and the initial key are also employed to obtain the security key, which can be used as input to the Lattice Hash. Besides, our algorithm utilizes the Paillier cryptosystem to encrypt the feature vector as the ciphertext image index for higher security. In addition, the 2D-Line map is improved and applied as a function for scrambling pixel positions to avoid the problem of storing pixel subscripts. Simulation experiments and security analysis shows that our proposed algorithm can resist differential attacks, statistical attacks, brutal attacks. Therefore, our scheme has good security performance and allows precise search over the ciphertext. [ABSTRACT FROM AUTHOR]

Robust reversible watermarking algorithms for images have good performance against traditional image processing methods such as compression, noise and filtering. However, when the sender transmits a carrier image over a noisy channel, the quality of the image is significantly affected and the receiver has difficulty recovering the secret information. To address this problem, we change the carrier of secret information from image to channel coding and propose a channel coding information hiding scheme based on uniform cyclic shift algorithm for images. The proposed algorithm, which is not based on a specific protocol, uses the error correction capability of the code to construct a covert channel. The secret information is embedded in the carrier bitstream approximately uniformly by the proposed algorithm, which makes the noise caused by the secret information similar to the random noise of the channel at low signal-to-noise ratio (SNR). We experimentally and analytically give the optimal values of some adjustable parameters and deduce the maximum embedding capacity of the proposed algorithm. Compared with the traditional robust reversible information hiding scheme, the carrier obtained by channel decoding at the receiving end can be the closest to the original carrier, and the secret information can be restored with the lowest bit error rate (BER). [ABSTRACT FROM AUTHOR]

An online estimation algorithm of landing footprints based on the drag acceleration-energy profile is proposed for an entry hypersonic vehicle. Firstly, based on the Evolved Acceleration Guidance Logic for Entry (EAGLE), drag acceleration-energy profiles are designed. To track the drag acceleration-energy profile obtained by the interpolation, a drag acceleration tracking law is designed. Secondly, based on the constraint model of the no-fly zone, flying around strategies are proposed for different conditions, and a reachable area algorithm is designed for no-fly zones. Additionally, by interpolating the minimum and maximum drag acceleration profiles, the terminal heading angle constraint is designed to realize the accurate calculation of the minimum and maximum downrange ranges by adjusting the sign of the bank angle. In this way, the distribution of landing footprints is more reasonable, and the boundary of a reachable area is more accurate. The simulation results under typical conditions indicate that the proposed method can calculate landing footprints for different situations rapidly and with the good adaptability. [ABSTRACT FROM AUTHOR]

A dynamic model of a two-axis rate gyro-stabilized platform-based seeker with cross-coupling, mass imbalance, and disturbance torque is developed on the basis of the working principle of seeker two-loop steady tracking theory; coordinate transformations are used to analyze the effects of seeker servo control mode on missile guidance and control systems. Frequency domain is used to identify the servo motor transfer function. Furthermore, a block diagram of the two-gimbal-coupled system is developed, and the coupling characteristics of gimbal angle are analyzed with different missile body inputs. Simulation results show that the analysis conforms with the actual movement rule of seeker gimbal and optical axis, and cross-coupling exists between the two gimbals. The lag compensation network can increase the open loop gain and increase the capacity for disturbance rate rejection. Simulations validate the theory and technology support for developing the seeker servo control model in engineering. [ABSTRACT FROM AUTHOR]