The need for secure communication in the advent of fully developed quantum computers is underscored by the ongoing standardization of Post-Quantum Cryptography algorithms (PQC). However, due to the complexity and long processing time of PQC algorithms, it is impractical to use them directly in most applications. Therefore, a practical implementation, especially in applications that may be vulnerable to quantum attacks, is essential. This paper proposes PQC-based and PQC-AES (Advanced Encryption Standard) hybrid Public Key Encryption (PKE) protocols to secure the communication of application data transmitted between two parties. The parties securely exchange their PQC keys using a PQC Key Encapsulation Mechanism (KEM) scheme. In the PQC-based PKE, the exchanged PQC public keys (asymmetric key cryptography) are used to encrypt data for network transmission. To decrypt the encrypted data, each party uses their private PQC secret key, known only to them, enabling secure end-to-end communication. In the PQC-AES hybrid PKE, a two-way shared secret key is used to generate a symmetric key (symmetric key cryptography) for encryption and decryption. The performance of the proposed protocols is evaluated through experiments with PQC algorithms in a client-server file transfer application. The evaluation results highlight the necessity of considering security, latency, and other metrics when implementing PQC algorithms in various applications. It is confirmed that KYBER1024 and BIKE-L1 achieved similar throughput in comparison to using the conventional AES-256 key encryption algorithm without extensive overheads in the wireless network for a smaller load (e.g., 1 KB size), while the PQC-AES hybrid cryptography protocol may be suitable for applications where the data size is larger,

Summary This article presents a tracing mechanism for group signatures answering the security threats of malicious authorities and users' forgeries. The proposal weakens the high trust placed on the centralized tracing party in previous group signatures by decentralizing tracing power using a multiple tracer setting and limiting the tracers' access using attribute‐based encryption and the requirement of the group manager's agreement. We allow the group manager to control tracers identifying his group users. Instead of a centralized tracer, our setting has multiple tracers possessing attribute sets. Thus, after getting the group manager's permission, a tracer should satisfy the access policy in a given signature to identify the signer. On the other hand, our group signature scheme decentralizes the tracing key generation and removes the group manager's tracing ability. Thus, it ensures that only the attribute‐satisfying and permitted tracers can identify the signer. Moreover, this article delivers security against malicious users. It presents a verification process of access policy of the signatures to prevent users from utilizing invalid attributes for signing. In addition, the article delivers a collaborative tracing mechanism to satisfy attribute sets that a tracer fails to fulfill alone for identifying a signer. Thus, our tracing mechanism ensures security against malicious authorities and group users in group signatures. The article gives the general construction of the scheme and discusses the security.

The challenge fueled by continuously increasing internet traffic is that in such networks with limited resources as mobile communications, excessive traffic creates a situation where continued service becomes impossible. Video traffic now accounts for 60% of mobile communication downlinks. Recent video streaming is adaptive-flow, which adjusts the bitrate to the delivery environment. This paper proposes a dynamical priority control method for core networks to solve the challenge of uninterrupted service due to excessive traffic and argues that our proposed method improves the service continuity of both adaptive-flows and non-adaptive-flows in a network where both coexist. Our method controls congestion by adjusting the priority used for input to the priority queue. The contribution of this paper is the demonstration that a network can increase its overall service continuity rate by controlling the priority on the network side by considering the bitrate adjustment function of adaptive-flows. Under congested network conditions, our proposed method improved service continuity by up to 40 % compared to a case where the adaptive-flow's priority was fixed.

We propose a decentralized but collaborative attribute-based tracing mechanism (a signer-identifying mechanism) for group signatures. Instead of a central tracing party in our scheme, a set of tracers satisfying the attribute set used for generating the group signature can identify the signer. Thus our proposal limits the parties who can identify the signer. On the other hand, it decentralized the tracing authority.

Stable and low-latency wireless communications are essential for the digital transformation in various industries. Multi-Diversity WLAN (MD-WLAN) incorporating three different types of diversities provides stable low-latency communications suitable for usages in many industries. In this demonstration, we explain the concept, design, and prototype of MD-WLAN, and then demonstrate the low-latency live video streaming over MD-WLAN using the prototype system. We confirm that multi-radio, multi-receiver, and FEC control of MD-WLAN contribute to the significant improvement of robustness and stability of low-latency video streaming.

Threats and risks against supply chains are increasing and a framework to add the trustworthiness of supply chain has been considered. In this framework, organisations in the supply chain validate the conformance to the pre-defined requirements. The results of validations are linked each other to achieve the trustworthiness of the entire supply chain. In this paper, we further consider this framework for data supply chains. First, we implement the framework and evaluate the performance. The evaluation shows 500 digital evidences (logs) can be checked in 0.28 second. We also propose five methods to improve the performance as well as five new functionalities to improve usability. With these functionalities, the framework also supports maintaining the certificate chain.

Stable wireless connections are required for realtime applications employing high data rate video streaming. Each of Multi-AP system and Multi-Link aggregation is effective to make WLAN connections stable, and we propose a combined Multi-AP Multi-Link system for realizing more stability in the practical use. In our proposed system, APs, which have different types of transmission queues, transmit a stream collaboratively with the support of a coordinator. In the demonstration, we will show that the proposed system realizes high quality video streaming even when WLAN links suffer from interference caused by surrounding devices.

In this paper, we advocate utilizing link-level broadcast of wireless LAN (WLAN) for real-time data transmissions from a drone to ground access points (APs) in order to enhance their robustness and spectral efficiency. A WLAN station (STA) is installed on a drone, which broadcasts its real-time data to surrounding multi-APs deployed over a ground field. In order to enhance the reliability of data transmissions, we also apply packet-level forward error correction (FEC). We conduct a field trial with our experimental testbed where all the above functions are implemented into the off-the-shelf WLAN equipment. Our experimental results show that multi-AP broadcast transmissions with packet-level FEC achieve better packet delivery ratio with smaller channel occupancy period than a common approach utilizing unicast transmissions.

Stable wireless connections are required for ITS applications employing real-time video streaming. It is effective to enable multiple links which work on different channels in order to make WLAN connections stable. Therefore, we propose a transmission control scheme for multi-link WLAN assuming the real-time video streaming. In our proposed scheme, radio units, which have different types of transmission queues, transmit a video streaming collaboratively with the minimum support of a coordinator. A multi-radio receiver controls A-MPDU transmissions of the radio units using Block-Acks including a shared scoreboard context to avoid duplicated retransmissions. Our simulation results show that the proposed scheme reduces both average latency and maximum latency of video streaming traffic significantly when wireless link conditions change dynamically.

Wireless network monitoring is a crucial tool for network administrators to manage wireless link quality in the indoor environments such as warehouses and factories. In this paper, we propose a comprehensive visualization system for correlative analysis between physical and MAC layer activities. In order to support various types of assessment tasks by the network administrators, the system provides a mode that performs quasi-realtime visualization of the ongoing traffic, and a mode that enables detailed assessment of the link quality for the past traffic by visualizing the data over an arbitrary time scale. We implemented the visualization system using ordinary PCs combined with the sensor node that calculates signal strengths from the observed radio signals and extracts the header information conforming to the IEEE 802.11 standards. We confirmed that the system has enough performance to visualize a large amount of data within a small latency and to achieve smooth operation while the time scale is changing.

We started a new research project in the “advanced 5G” era that aims at accommodating various types of communications involving current and emerging services with different data flow-level quality requirements. In this paper, the objectives and the technical aspects of the research project are introduced. We propose an architecture based on a virtualized radio access network (vRAN) that enables adaptive control of equipment resources and location of functions in the vRAN environment in accordance with spatially and temporally changing communication demands. The seven planned research items that are essential for realizing the advanced 5G network are listed as follows: blockage prediction, new radio access technologies (RATs) and their implementations with software-defined radio (SDR), adaptive interference and resource control, integration of radio and fiber resource control, highly efficient access transmission control, adaptive placement of BS functions, and quality aware traffic pattern prediction.

In this demonstration, we show that on a device with multiple network interfaces, our proposed network selection method can select a proper interface based on measured delays and information flags with an ICMP reply packet in an edge computing (EC) environment. The methods mainly provide the following two features: the resolution of FQDN through multiinterfaces and the insertion of EC and congestion flags into an ICMP reply packet. These features enable the practical usage of multi-interfaces on a device to select a proper network interface for advanced services and applications based on EC. This paper first explains the features and the procedures of our method. Then our demonstration shows that the device can select a proper interface based on the flag information.

To facilitate introduction of IoT devices to the environments such as factories and hospitals, it is desirable that the network administrators can accurately monitor the conditions of wireless networks. In the existing schemes or products, physical layer information and MAC layer information are often acquired and analysed individually. In this paper, we propose a sensing system that allows synchronized time series analysis between physical and MAC layers for detailed quality assessment of wireless links. By synchronizing the data from physical and MAC layers, we show that it is possible to identify the cause of frame losses, which occurred due to a hidden terminal problem. We implemented a prototype sensor node using an FPGA and conducted an experiment to acquire the data from both layers. From the experiment, we confirmed that the prototype sensor node has enough performance on time synchronization and resolution between cross layered data.

In this paper, we investigate personality estimation from Japanese weblog text. Among various personality types, we focus on Egogram, which has been used in Transactional Analysis and is strongly related to the communicative behavior of individuals. Estimation is performed using the Multinomial Naïve Bayes classifier with some feature words that are selected based on the information gain. The validity of this approach was evaluated with real weblog text of 551 subjects. The results show that our approach achieved 12-25% improvement from baseline. The feature words selected for the estimation are strongly correlated with the characteristics of Egogram.

In this paper, we propose a conversational virtual agent application in mobile phone which covers the lack of interactivity of unidirectional private communication. In this application the agent automatically recognize user situation, such as location, locomotion and interruptability using sensors installed in mobile phone. The agent also behaves as if the target person which user wants to contact with behaves based on the Egogram estimation from weblog of this target user. In preliminary experiments, the estimation methods using in this application achieve sufficient accuracy for our purpose at this stage.

This paper describes a new multicast scheduling scheme for multi-massive-online (MMO) applications in mobile networks. In order to reduce the amount of traffic volume, multicast channels should be fully utilized for information sharing among users while unicast channels are used to notify the current states of the users to the servers. On the other hand, most mobile terminals cannot use both multicast and unicast channels at the same time slot. In such case, each terminal should choose either to receive data in multicast channels delivered from the servers, or to send its state information to the servers while missing the multicasted data In order to provide the optimum tradeoff between sending and receiving the relevant data of MMO, we propose a new scheduling algorithm with which multicast servers enable most mobile terminals to have upload time while they obtain the multicast contents that they prefer. The effectiveness of the proposed algorithm is numerically evaluated.

We developed an FPGA-based content delivery system to securely distribute digital content on the Internet. With partial reconfigurability of a Xilinx Virtex-Il Pro FPGA, the system provides a flexible single-chip solution for protecting digital content. In the system, a partial circuit must be downloaded from a server to the client terminal to play content. Content will be played if and only if the downloaded circuit is correctly combined (= interlocked) with the circuit built in the terminal. Since each circuit has a unique I/O configuration, the downloaded circuit interlocks with the corresponding built-in circuit designed for a particular terminal. Thus, the interface of the circuit itself provides a novel authentication mechanism. In the present paper, we describe the detailed architecture of the proposed system and clarify the feasibility and effectiveness of this system experimentally using a single-chip partial reconfiguration. In addition, we discuss the fail-safe mechanisms, partially reconfigurable FPGA architecture, and future research necessary for the practical application of the system.

A secure content distribution system is prototyped based on run-time partial reconfigurability of an FPGA. The system provides a robust content protection scheme for online content download services. The key idea is to divide the security module in a user terminal into Content-Specific Circuit (CSC) and Terminal Build-in Circuit (TBC) and to dynamically reconfigure CSC. CSC is customized for each content and transferred from a server in the form of encrypted configuration data. TBC is a uniquely identifiable processing unit that is combined with particular CSC to decrypt and decode contents. A content is properly decrypted and played by the security module only if its CSC is interlocked with the authorized TBC. To realize this CSC-TBC interlock authentication mechanism, partial reconfigurability of the FPGA is essential. This paper discusses the robustness and feasibility of the content distribution system through a proof-of-concept demonstration.

Customer retrial is a common feature in practical service systems. This paper develops an analytical approach that incorporates reduced load analyses employing a retrial model, and investigates the effect of request retrials on the performance of wavelength-routed optical networks. The analytical approach can evaluate network performance in terms of request blocking probability, request loss probability, and total carried traffic. We analyze a representative network (NSFnet) with different retrial features and validate the proposed approach with simulation experiments. Analytical results indicate that the retrials increase the blocking rates of fresh request while decreasing the request loss rate, thus leading to a high total carried traffic in a network. For the routing schemes used in this work, the analytical results set a lower bound to the request loss probability and an upper bound to the total available traffic. The developed model allows performance analyses and service optimisation including customer retrials.

We propose a new architecture for a content protection system that conceals confidential data and algorithms in an FPGA as electrical circuits. This architecture is designed for a client-server type on-line contents distribution services. The key component of this architecture is the digital content security circuit that is dynamically configured on the FPGA and performs the signal processing such as certification and decryption for replaying digital contents. The digital content security circuit is composed of two different circuits. One is the content-specific circuit that is built from the configuration data generated by the server. This circuit is specialized for each item of digital content. The other is the terminal built-in circuit that is uniquely programmed and implemented for each terminal, and is not open for the others. The content-specific circuit properly works only if it is combined with the terminal built-in circuit of the authorized client. We prototype and demonstrate a proof-of-concept model of the FPGA-based content protection system applicable to embedded consumer electronics such as set top boxes and cell phones.

The basic concept of a novel architecture called statistical lambda multiplexing network (SLAMNet) was proposed to provide a pair of routers with multiple transparent wavelength paths in a dense wavelength division multiplexing (DWDM) network. The architecture achieves statistical multiplex gain in use of limited wavelength resources by dynamically adjusting the number of wavelength paths according to the volume of traffic on a best-effort basis. The most striking feature of the architecture is to switch the wavelength paths without signaling between nodes operated asynchronously. Fundamental performance of the architecture was verified on an experimental system. The basic concept assumes a single hop network of switched wavelength paths, and the assumption limits flexibility and efficiency of network operation. In this paper, the basic concept is extended in order to apply SLAMNet to a multihop network of switched wavelength paths. Based on the extended concept, circuit-based and burst-based wavelength path assignment methods are discussed as implementation scenarios of the architecture.

We propose a new architecture called Statistical Lambda Multiplexing Network (SLAMNet) for a future photonic network multiplexing hundreds wavelengths. The major objective of the SLAMNet is efficient use of network resources such as wavelengths and facilities. In the SLAMNet, optical channel (OCh) paths are managed in two logical layered networks in order to adapt to wide-range time-scale variations of offered traffic load. Based on the architecture, we also suggest an adaptive OCh path assignment mechanism that works without signaling processes. In this paper, we describe the proposed architecture and path assignment mechanism and furthermore, numerically evaluate their effectiveness.