Strong Anonymous Communication System Based on Segment Routing Over SDN

Anonymous communication technology has been proposed to conceal the identity and communication relationship of both parties in communication, mitigating the threats of communication surveillance. However, the traditional anonymous communication scheme is designed on the traditional network architecture, network devices have limited control over the network, which leads to the inefficiency of anonymous communication. Software Defined Networks (SDN) is a novel network architecture that manages network through controller. It has the characteristics of high efficiency and flexibility. However, in recent years, researches about anonymous communication of SDN exist many challenges, such as limitation of scenarios and lack of anonymity. To address these challenges, this paper, inspired by pseudonym changing, proposes a pseudonym-based anonymous routing mechanism under multi-controller SDN architecture, in which pseudonym-changing is used for hiding the identity of the communicating parties. Besides, to avoid routing error caused by address conflicts, an effective hash checking method is proposed to avoid anonymous address conflicts. Based on that, we also present an anonymity enhanced scheme that employs phantom routing to hide the sender in the routing path and a multicast mechanism to prevent traffic analysis attacks. Anonymity analysis and experiment show that this scheme can provide strong anonymity protection for distributed SDN without much time cost, and has good practicability.

With the continuous development of the Internet and communication technologies, network communication provides convenience but also brings security problems such as exposure of users' personal privacy information and theft, private tampering, and forgery of false information. Modern cryptography technology is an important safeguard against message eavesdropping and tampering, while the rapidly developing anonymous communication technology in this century makes it difficult for attackers to infer user's personal information and communication relationships. In response to the potential threats of traditional centralized systems such as central nodes being vulnerable to attacks and data storage being tampered with, this paper proposes a blockchain anonymous communication algorithm KDAC based on key derivation, which takes advantage of the decentralization, data immutability, consensus mechanism and anonymity of blockchain and combines the ECC cryptographic derivation algorithm and anonymous communication technology to realize the key-at-a-time, one-address-at-a-time The key derivation scheme ensures the message integrity and tamper-evident while effectively hiding the identity information of both communication parties. In addition, this paper also optimizes the blockchain anonymous communication system with key derivation. Users only need the initial key of blockchain nodes to join the network for communication, and the information transmission is difficult to trace based on the blockchain network, which can effectively guarantee communication security and anonymity. The experimental results show that the efficiency of the derived key algorithm is roughly in the same order of magnitude as that of the 256-bit AES symmetric encryption algorithm, which can play a better role in practical applications. On the other hand, the derived key generated based on the algorithm has complete randomness in association verification, and it is impossible to reverse the initial parameters, which can well guarantee the anonymity of user identity.

Anonymous communication in social network is an effective way to protect users privacy. This study aims to conduct comparative analyses on different anonymous communication schemes in social network by grouping them into three groups' as Onion Router schemes, Ring Router schemes and the techniques that are not related to Onion and Ring schemes. The text extracts the main impact factors and mechanism in these current latest schemes to identify strengths and limitations of each schema. Then, a universal anonymous communication scheme model in social network will be proposed. This new model applies ring structure and onion encryption in the circuit, where the hidden server is part of the ring.

Anonymity is increasingly important for network communications concerning about censorship and privacy. Early research on source anonymous communication protocols generally stems from mixnet and DC-net. They either cannot provide provable anonymity or suffer from transmission collision. To solve this problem, a k-anonymous protocol based on hierarchical ring structure and mix technique was proposed. This proposed protocol is collision free and provides provable k-anonymity for both the sender and the recipient. However, this protocol requires the trustworthiness of k honest nodes, therefore, anonymity is only conditional. Alternatively, in this paper, we propose a provably secure anonymous communication (PSAC) scheme without relying on any trusted third parties. While ensuring the message sender anonymity, it can also provide message content authenticity. The proposed PSAC scheme can prevent tracing the senders of messages and limits the disruption that can be caused by participants.

A least load dispatching algorithm for distributing requests to parallel Web server nodes is described. In this algorithm, the load offered to a node by a request is estimated based on the expected transfer time of the corresponding reply through the Internet. This loading information is then used by the algorithm to identify the least load node of the Web site. By using this algorithm, each request will always be sent for service at the earliest possible time. Performance comparison using NASA and ClarkNet access logs between the proposed algorithm and commonly used dispatching algorithms is performed. The results show that the proposed algorithm gives 10% higher throughput than that of the commonly used random and round-robin dispatching algorithms.

In recent years, Big data has attracted more and more attention. The strategic significance of big data technology is not to master huge data information, but to professionally process these meaningful data. The emergence of big data technology has made the Internet of Things a reality. Among them, wireless sensor networks (WSNs) have been widely used in military, medical and other fields. WSNs can be used to realize data collection, processing and transmission. However, in the process of message forwarding and data aggregation in WSNs, there are problems such as node’s real identity, key and data leakage. The adversary can use this information to disrupt communication and attack important nodes. In resource-constrained WSNs, we propose an anonymous communication scheme between nodes based on pseudonyms and bilinear pairing. Firstly, we use pseudonyms instead of real identities to receive and forward messages to achieve node anonymity. Secondly, based on bilinear mapping operation and hash-based message authentication code (HMAC), we achieved key agreement between nodes and verification of message integrity to protect data security. In addition, we propose the energy-based link direction selection protocol, which ensures that the message can reach the base station without passing too many nodes, thus saving network resources to a certain extent. The anonymous communication scheme between nodes based on pseudonyms and bilinear pairing ensures the anonymity, reliability and security of communication in WSNs, and ensures low overhead in storage, computation and communication.

Anonymous technology is an effective way for protecting users’ privacy. Anonymity in sensor networks is to prevent the unauthorized third party from revealing the identities of the communication parties. While, in unstable wireless sensor networks, frequent topology changes often lead to route-failure in anonymous communication. To deal with the problems of anonymous route-failure in unstable sensor networks, in this paper we propose a fully anonymous routing protocol with self-healing capability in unstable sensor networks by constructing a new key agreement scheme and proposing an anonymous identity scheme. The proposed protocol maintains full anonymity of sensor nodes with the self-healing capability of anonymous routes. The results from the performance analysis show that the proposed self-healing anonymity-focused protocol achieves full anonymity of source nodes, destination nodes, and communication association.

Polar codes are of great interest, since they are the first provably capacity-achieving forward error correction codes. To improve throughput and to reduce decoding latency of polar decoders, maximum likelihood (ML) decoding units are used by successive cancellation list (SCL) decoders as well as SC decoders. This paper proposes an approximate ML (AML) decoding unit for SCL decoders first. In particular, we investigate the distribution of frozen bits of polar codes designed for both the binary erasure and additive white Gaussian noise channels, and take advantage of the distribution to reduce the complexity of the AML decoding unit, improving the throughput-area efficiency of the SCL decoders. Furthermore, a multimode (MM) SCL decoder with variable list sizes and parallelism is proposed. If high throughput or small latency is required, the decoder decodes multiple received words in parallel with a small list size. However, if error performance is of higher priority, the MM-SCL decoder switches to a serial mode with a bigger list size. Therefore, the MM-SCL decoder provides a flexible tradeoff between latency, throughput, and error performance at the expense of small overhead. Hardware implementation and synthesis results show that our polar decoders not only have a better throughput-area efficiency but also easily adapt to different communication channels and applications.

In this paper, we present a novel systolic architecture for high-throughput computation of 3-dimensional (3-D) discrete wavelet transform (DWT). The entire 3-D DWT computation is decomposed into three distinct stages and implemented concurrently in a linear array of fully pipelined processing elements (PE). The proposed structure for 3-D DWT provides higher throughput than the existing architecture; and involves nearly half or less the number of multipliers and adders; and less on-chip memory (when normalized for unit throughput rate) than the other. Most importantly, the proposed one does not require any frame buffer unlike the other to perform inter-frame DWT computation. The proposed structure has a small latency and can perform 3-D DWT computation with 100% hardware unitization efficiency.

Information reconciliation is a crucial procedure in the classical post-processing of quantum key distribution (QKD). Poor reconciliation efficiency, revealing more information than strictly needed, may compromise the maximum attainable distance, while poor performance of the algorithm limits the practical throughput in a QKD device. Historically, reconciliation has been mainly done using close to minimal information disclosure but heavily interactive procedures, like \textit{Cascade}, or using less efficient but also less interactive ---just one message is exchanged--- procedures, like the ones based in low-density parity-check (LDPC) codes. The price to pay in the LDPC case is that good efficiency is only attained for very long codes and in a very narrow range centered around the quantum bit error rate (QBER) that the code was designed to reconcile, thus forcing to have several codes if a broad range of QBER needs to be catered for. Real world implementations of these methods are thus very demanding, either on computational or communication resources or both, to the extent that the last generation of GHz clocked QKD systems are finding a bottleneck in the classical part. In order to produce compact, high performance and reliable QKD systems it would be highly desirable to remove these problems. Here we analyse the use of short-length LDPC codes in the information reconciliation context using a low interactivity, \textit{blind}, protocol that avoids an a priori error rate estimation. We demonstrate that $2 \times 10^3$ bits length LDPC codes are suitable for blind reconciliation. Such codes are of high interest in practice, since they can be used for hardware implementations with very high throughput.

We introduce one-way LOCC protocols for quantum state merging for compound sources, which have asymptotically optimal entanglement as well as classical communication resource costs. For the arbitrarily varying quantum source (AVQS) model, we determine the one-way entanglement distillation capacity, where we utilize the robustification and elimination techniques, well-known from classical as well as quantum channel coding under assumption of arbitrarily varying noise. Investigating quantum state merging for AVQS, we demonstrate by example, that the usual robustification procedure leads to suboptimal resource costs in this case.

Federated learning (FL) is an emerging machine learning (ML) paradigm used to train models across multiple nodes (i.e., clients) holding local data sets, without explicitly exchanging the data. It has attracted a growing interest in recent years due to its advantages in terms of privacy considerations, and communication resources. In FL, selected clients train their local models and send a function of the models to the server, which consumes a random processing and transmission time. The server updates the global model and broadcasts it back to the clients. The client selection (CS) problem in FL is to schedule a subset of the clients for training and transmission at each given time so as to optimize the learning performance. In this paper, we present a novel multi-armed bandit (MAB)-based approach for CS to minimize the training latency without harming the ability of the model to generalize, i.e., to give reliable predictions for new observations. We develop a novel algorithm to achieve this goal, dubbed Bandit Scheduling for FL (BSFL). We analyze BSFL theoretically, and show that it achieves a logarithmic regret, defined as the loss of BSFL as compared to a genie that has complete knowledge about the latency means of all clients. Furthermore, simulation results using synthetic and real datasets demonstrate that BSFL is superior to existing methods.

Dual Split-Merge: A high throughput router architecture for FPGAs

This paper studies the capacity of hybrid wireless networks with opportunistic routing (OR). We first extend the opportunistic routing algorithm to exploit high speed data transmissions in infrastructure network through base stations. We then develop linear programming models to calculate the end-to-end throughput bounds from multiple source nodes to single, as well as, multiple destination nodes. The developed models are applied to study several hybrid wireless network examples. Through case studies, we investigate several factors that have significant impacts on the hybrid wireless network capacity under opportunistic routing, such as node transmission range, density and distribution pattern of base stations (BTs), number of wireless channels on wireless nodes and base stations, etc. Our numerical results demonstrate that opportunistic routing could achieve much higher throughput on both ad-hoc and hybrid networks than traditional unicast routing (UR). Moreover, opportunistic routing can efficiently utilize base stations and achieve significantly higher throughput gains in hybrid wireless networks than in pure ad-hoc networks especially with multiple-channel base stations.

Network coding provides a new perspective for anonymous communication. Wang et al. propose an anonymous communication scheme named ALNCode, in which the linear relation of the global encoding vectors can be hidden without the participation of encryption/decryption operations. But the effectiveness of the scheme needs to be further analyzed. In this paper, we present an exact formula of the effectiveness of ALNCode scheme, which goes a step further than the lower bound given by Wang et al.. Based on the exact formula, the influential factors of effectiveness of the scheme are taken into account in details. Moreover, a comparison between the exact effectiveness and the lower bound shows that the lower bound is not true. The reason of the error is analyzed finally.