With the rapid development of communication technologies in marine environments, the privacy and integrity of transmitted data have become important security issues. The security and resource consumption of existing privacy-preserving data aggregation schemes are not suitable for application to underwater acoustic communications. To address the above issues, this article proposes an NTRU lattice edge aggregation scheme based on underwater acoustic communication. Specifically, the scheme protects the data by perturbing it through edge differential privacy, and then encrypts the perturbed data using a lattice-based encryption method. In addition, it utilizes the NTRU lattice-based batch signature verification method to verify signatures in batch, which improves the verification efficiency. The pseudo-identity of nodes and timestamps are also utilized to enhance the security of the scheme. The edge computing model is utilized to reduce the high delay in underwater acoustic communication and to reduce the wastage of the resource in the underwater acoustic communication. Security and performance analysis conducted through simulation experiments show that our scheme is resistant to quantum attacks and achieves differential privacy with low computational and communication cost overheads.

In order to cope with the problem of how to agree on a covert secret key with high reliability and strong secrecy among an arbitrary number of legitimate nodes in underwater acoustic channel (UAC), a Covert Secret key agreement scheme based on underwater acoustics dynamic hypergraph called CSDH is proposed. The CSDH scheme is novel in three aspects. First, we utilize attention mechanism for extracting the feature of node in UAC and construct a dynamic hypergraph model by its characteristics, which has less storage space and lower computational complexity. Second, we design a spatio-temporal hypergraph convolution method based on the spatial and temporal variation characteristics of UAC in which the number of the nodes is arbitrary, the hyperedge is dynamic, and each hyperedge can encompass an arbitrary number of nodes. Third, we utilize covert communication and polar coding to construct high-entropy bit indices set and very high-entropy bit indices set to generate a common covert key among arbitrary number of legitimate nodes to ensure that not only the key is secret but the entire key agreement process remains covert to eavesdroppers. The reliability, uniformity, secrecy, covertness and secrecy capacity of the CSDH scheme are proved by the information theory and hypergraph theory. The simulation results demonstrate the performance of the CSDH scheme is better than that of existing schemes.

To address the issue of data confidentiality and security in underwater acoustic sensor networks (UASNs), a NTRU-based Adaptive Data Hiding scheme calledNADHis proposed. TheNADHscheme is novel in two aspects. First, we propose a weighted interpolation approach based on information entropy to enhance both data security and embedding capacity. Second, we propose an adaptive coefficient selection mechanism to monitor environmental changes in real time and adjust the data embedding strategy to maximize embedding capacity. This letter also provides a theoretical analysis of the correctness and security of the NADH scheme, and proves the upper bound of its mean squared error (MSE). Experimental results show that when the embedding capacity ofNADHis 2048 bits, the MSE is 0.7495, the average peak signal-to-noise ratio (PSNR) is 49.792 dB, and the average structural similarity index (SSIM) is 0.9998, outperforming existing data hiding schemes.

The intrinsic qualities of the underwater acoustic channel (UAC), such as multipath propagation and motion-induced Doppler shift, may result in large direction of arrival (DOA) estimation bias. In this paper, we propose a two-dimensional DOA estimation method for the underwater acoustic signals with gain-phase errors, coined as ML-ANM (Maximum Likelihood-Atomic Norm Minimization). We assume that the number of received signals satisfies the parameter identifiability condition. First, we propose a bimodal atomic norm involving noncoherent and coherent signals under the maximum likelihood estimation (MLE) framework, which allows simultaneous processing of noncoherent and coherent signals without decorrelation. To avoid the direct calculation of gain-phase errors, we transform the primal MLE optimization model into an ML-ANM optimization problem with two positive semidefinite constraints. Second, we utilize oblique projection to divide the optimal problem into two optimal subproblems involving noncoherent and coherent signals, and prove the equivalence of the problems and their solutions. Then, we obtain the global optimal solutions for the two optimal subproblems. Third but not the least, we provide the Cramér-Rao lower bound (CRB) and prove that the asymptotic error covariance matrix of ML-ANM achieves the CRB. Extensive experiments through realistic ocean simulations demonstrate the effectiveness of the ML-ANM method.

Underwater acoustic communication has been recognized as an enabling technology for various applications in the maritime domain. Aiming at the problem of how to ensure the safe and complete transmission of underwater information under the condition of security and privacy, an NTRU certificateless aggregate signature scheme for underwater acoustic communication is proposed. The proposed scheme describes the generation of pseudo-identity through the polynomial fitting formula of the underwater acoustic channel, and constitutes the complete private key of node privacy with the secret value. On this basis, a signature combined with timestamp is designed by using ocean noise polynomial and homomorphic hash function, and the aggregate signature is further calculated. Our results demonstrate the efficiency of the scheme in terms of computational overhead and signature length.

Ships as moving vehicles have intermittent connectivity and are connected to one another via ad-hoc networks with directional antennas. We refer to such Internet of Ships as IoSNET. Neighbor discovery (ND) is a fundamental requirement and a building block in an IoSNET. However, existing directional antenna-based ND protocols are known to be vulnerable under multi-end wormhole attacks. By analyzing such vulnerabilities, we propose a Directional Antennas powered SEcure Neighbor Discovery protocol, coined asDASEND, for protecting IoSNET against two-end and multi-end wormhole attacks. TheDASENDprotocol is novel in two aspects. First, we construct two timing constraints for detecting the wormhole attacks using a linear clock model without strict time synchronization and propose a message authentication mechanism for ensuring the security of the time stamps. Second, we propose a virtual grid structure to model the relative locations of transmitters jointly using their direction-of-arrival (DOA) and received signal strength (RSS) values. Based on this model, we propose a beam state-based steering approach to shorten the discovery latency of the ND process. Extensive experiments through IoSNET simulations demonstrate the effectiveness of ourDASENDprotocol for delivering secure neighbor discovery as a service in the Internet of Ships environment under different movement scenarios.

The unique characteristics of underwater channels, such as the mobility of sensor nodes, require robust and efficient security mechanisms for secure and efficient data collection in mobile underwater sensor networks (UWSNs). In this paper, we propose a novel three-tier framework for securing data collections in mobile UWSNs, called SenseVault. First, to support both the authentication of intra-cluster nodes and the authentication of inter-cluster nodes, we propose a cubic cluster formation approach to adapt to dynamic environments with flexible split and merge operations, and use cryptographic hash functions to derive secret keys for the authentication of nodes moving among the clusters. Second, we design a lightweight node revocation and authentication key update mechanism based on higher-order polynomial. To provide strong resilience against misbehavior of the compromised cluster head, we further introduce a Tripartite Cooperation Update (TCU) scheme by leveraging the cooperation among surface stations, safe neighboring cluster heads, and safe intra-cluster members. Third, we propose a deterministic quantization approach, called Virtual Phase Shift (VPS) for the secure generation of secret keys at the physical layer. Extensive experimental results demonstrate the effectiveness of the proposed framework under different scenarios.