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As automotive embedded systems comprised of electronic control units (ECUs) connected via a controller area network (CAN) have continued to develop, the volume of information these systems are required to handle has also rapidly increased. Cyber attacks targeting vulnerable points of automotive embedded systems in particular are on the rise to hinder normal operation of a vehicle. However, adding security mechanisms to defend against attacks cannot neglect timing requirements in terms of vehicle safety. This is because it may lead to a violation of automobile safety. In short, both sides of this issue must be addressed from the outset of the system design stage to provide optimal security and safety. As a response to this pressing issue, we propose a novel and efficient scheme. The design optimization during the system design phase not only ensures all the real-time applications are executed within their deadline but also reduces the number of transmitted messages over the CAN bus. After optimization, we apply a hash message authentication code (HMAC) to specific messages, providing secure communication between ECUs and protecting against cyber attacks. Security analysis and experimental results prove that the proposed scheme can counter attacks on the CAN bus while meeting timing requirements. Therefore, our proposed scheme is effective in satisfying improvement of both safety and security.

A new method for observing the outermost surface morphology and the thickness of solid electrolyte interphase (SEI) are presented. Low acceleration voltage in extreme high resolution scanning electron microscopy (XHR-SEM) provides detailed information on the SEI surface morphology due to secondary electron contrast mechanism. Also, XHR-SEM under low acceleration voltage with low energy induced ion etching in x-ray photoelectron spectroscopy (XPS) studies provides valuable information on the SEI layer thickness. More detailed properties of the SEI layer were investigated by transmission electron microscopy (TEM).

Trends in software distribution indicate a rapid change in an online application market. Current smartphones enable users to easily install various applications that are purchased from the online market using their phone. In addition, the openness of the Android system even allows users to choose from various online markets. Because such openness also invokes critical threats such as malware and illegal use, several online markets employ strong authentication techniques. However, such methods can also inconvenience valid users. In this paper, we discuss such problems and propose the concept of an authentication model that makes purchased applications available in most cases.

Google Android provides market based application distribution to provide ease use of application services. While openness of Android allows various ways of application distribution, including installation of unsigned application. such openness also invokes critical threats such as the spread of malwares and the illegal distribution of applications. In order to prevent such threats, several distributors use on-line authentication techniques by using mobile subscriber`s information. However such methods also have limits that even legal users cannot use their purchased application in situations. Therefore, in this paper, we discuss such problems and provide some ideas of authentication method that allow users to use their purchased application when users change their status.

The Radio Frequency for Consumer Electronics (RF4CE) is developed to support the rapid increasing demand of bi-directional communication and remote control functionalities in CE market such as TV, home theater . However, current security model in RF4CE standard has potential weakness that transmission of initial key seeds is operated via unencrypted air interface. In this paper, we propose a secure key agreement protocol that uses pre-shared information between consumer devices and manufacturers and controllers receive the information by communication with manufacturers.

User authentication scheme is an important issue for providing secure roaming service to users of mobile devices. In 2008, Wu, Lee and Tsaur proposed an enhanced anonymous authentication for roaming environment. In this paper, we show weaknesses of Wu–Lee–Tsaur’s schemes such as failing to achieve anonymity and perfect forward secrecy, and disclosing of legitimate user’s password. Therefore, we propose a new enhanced scheme that uses Elliptic Curve Diffie–Hellman (ECDH) to overcome these weaknesses and improve performance. We also demonstrate that our scheme not only overcomes these weaknesses but also provides mutual authentication and resistance to a man-in-the-middle attack. Compared with previous schemes that use public key cryptosystem with certificates, our scheme is more efficient. Moreover, our scheme does not use timestamps, so it is not required to synchronize the time.

Vertical handoff is one of the most important issues in the heterogeneous networks. While Lee et al. introduced a selective advance reservations and resource-aware handoff direction (SARAH) mechanism in order to provide a fast and efficient handoff with combination of layer 2 (L2) and layer 3 (L3) communications, there was a drawback that there was no consideration of handoff between heterogeneous network. In this paper, we improve the mechanism by providing security functions such as the neighbor-mapping server that binds IP address and MAC address with security support. At first, we discuss security issues in SARAH and proposed enhanced protocol. Finally, we show simple implementation results of our design in order to verify the practical aspects of our design.

The advent of converged environment merged with wireless sensor networks (WSNs) and mobile networks can have the possibility on enabling us to experience variety of ubiquitous applications based on multi-sensor attached smartphones. However, most of current researches are failed to recognise the fact that there are many drawbacks to break through between the heterogeneous networks such as a WSN and mobile network. In this study, the authors propose the authentication and key agreement protocol that efficiently reduces the overall computational and communication costs in the next generation converged network. The enhanced security procedures are operated through the mobile network in order to maximise the lifetime of the sensor networks and to apply the combined capabilities of both networks. The authors show the presented novel design can show the feasibility to minimise the usage of the sensor networks with the battery-powered sensors in comparison with the existing authentication models, and can be deployed under the standard architectures.

Employing public key-based security architecture is inevitable for the advanced security applications in the mobile networks. However, key storage management problems have arisen, because the public key computation is still the large overhead to USIM, and the mobile equipment has potential threats of the key leakage or loss. In order to solve such shortcomings, we improve the key-insulated models and propose "Trust Delegation" model that the overall security computations are operated in ME, while the initial private key still remains in the secure storage in USIM. Our model is resilient against not only key exposure but also key loss. Finally, we show that the overall transactions can be reduced to one-third than current 3GPP Generic Authentication Architecture.

Wireless sensor networks improve the quality of human daily life like ubiquitous city and healthcare services as well as the fundamental monitoring such as environment pollution, tunnel monitoring, earthquake diagnostic, and so on. To increase usability and feasibility of collected sensor data, a wireless sensor network should be required to apply a variety of mobile devices to give the information at anytime and anywhere to users. Thus, we present multi-sensor centric smart sensor network architecture using general mobile devices in order to provide more efficient and valuable sensor network application and services. The proposed system architecture is based on IEEE 802.15.4-2006 standard with smart mobile devices. We also show some scenarios with on-demand request and real time event driven data to show the feasibility of the proposed architecture using five kinds of sensors such as magnetic, photodiode, microphone, motion and vibration. Based on the experiment results, we show that the proposed system has the potential as smart mobile device-based wireless sensor network architecture.

Key escrowing is one of the core technologies for the lawful interception (LI) of secure communications in the wired and wireless networks. Although many previous studies on the key escrowing have been done before, they are insufficient to be deployed in practical networks due to conflicts with the LI requirements. Moreover, there is lack of consideration on the LI of ID-based cryptosystem (IDBC)-based secure communication because the interest of the LI was moved to the industries and IDBC has the inherent key escrowing property. However, the inherent property of IDBC cannot prevent ‘illegal’ eavesdropping of all the communications in the networks from the law enforcement agency with the ‘legally’ obtained key. Thus, we propose a new key escrow model that satisfies the requirements of LI and overcomes the potential threats of IDBC. Our contributions enable the scalable and efficient key escrowing for the LI of secure one-way and two-pass communication in the mobile networks. Copyright © 2010 John Wiley & Sons, Ltd. (A part of this paper was presented in IEEE International Conference on Consumer Electronics '09 [1].)

Recent Location Based Services (LBS) extend not only information services such as car navigation services, but supporting various applications such as augmented reality and emergency services in ubiquitous computing environments. However location based services in the ubiquitous computing environment bring several security issues such as location privacy and forgery. While the privacy of the location based service is considered as the important security issue, security against location forgery is less considered. In this paper, we propose improved Han et al.'s protocol [1] that provides more lightweight computation. Our proposed model also improves the credibility of LBS by deploying multiple location sensing technologies.

The VoIP-based Internet Phonesystem is now seen as one of the killer applications in the high speed and broadband internet environment. Given the wide-spread use of the Internet Phone, it is necessary to provide security services for guaranteeing users' privacy. However, providing security service in Internet Phone has the possibility of incurring additional overheads such as call setup delay time. In this paper, we present a one-way key agreement model based on VoIP in order to reduce call setup time as well as protecting user privacy. The proposed approach decreases the delay time of the call setup in comparison with the previous models because our model enables the key generation in caller side without waiting the response from the receiver.

A zirconia gel/polymer hybrid nanofiber was produced in a nonwoven fabric mode by electrospinning a sol derived from hydrolysis of zirconium butoxide with a polyvinyl butyral. Results indicated that the hydroxyl groups on the vinyl alcohol units in the backbone of the polymer were involved in the hydrolysis as well as grafting the hydrolyzed zirconium butoxide. In addition, use of acetic acid as a catalyst resulted in further hydrolysis and condensation in the sol, which led to the growth of -Zr-O-Zr- networks among the polymer chains. These networks gradually transformed into a crystalline zirconia structure upon heating. The as-spun fiber was smooth but partially wrinkled on the surface. The average fiber diameter was 690±110 ㎚. The fiber exhibited a strong but broad blue photoluminescence with its maximum intensity at a wavelength of ~410 ㎚ at room temperature. When the fiber was heat-treated at 400℃, the fiber diameter shrunk to 250±60 ㎚. Nanocrystals which belonged to a tetragonal zirconia phase and were ~5 ㎚ in size appeared. A strong white photoluminescence was observed in this fiber. This suggests that oxygen or carbon defects associated with the formation of the nanocrystals play a role in generating the photoluminescence. Further heating to 800℃ resulted in a monoclinic phase beginning to form In the heat-treated fibers, coloring occurred but varied depending on the heating temperature. Crystallization, coloring, and phase transition to the monoclinic structure influenced the photoluminescence. At 600℃, the fiber appeared to be fully crystallized to a tetragonal zirconia phase.

Currently, it is rapidly increasing convergence services based on various mobile devices with sensors like Smart Home. Specifically the mobility of the sensors in Smart Home merged with wireless sensor networks (WSN) brings security issues such as re-authentication and tracing the node movement. We extend our novel and efficient node authentication and key exchange protocol that support Irregular distribution. Compared with previous protocols, our protocol has only a third of communication and computational overhead. We expect our protocol to be the efficient solution that increases the lifetime of sensor network.

Mobility of sensor node in Wireless Sensor Networks (WSN) brings security issues such as re-authentication and tracing the node movement. However, current security researches on WSN are insufficient to support such environments since their designs only considered the static environments. In this paper, we propose the efficient node authentication and key exchange protocol that reduces the overhead in node re-authentication and also provides untraceability of mobile nodes. Compared with previous protocols, our protocol has only a third of communication and computational overhead. We expect our protocol to be the efficient solution that increases the lifetime of sensor network.

Thermal and microwave irradiation treatment of Ti(OPri)4 and Zr(OBu)4 leads to the formation of homogenous and transparent oxo-alkoxy derivatives of titanium and zirconium in a quantitative yield. The oxo-alkoxy derivatives were characterized with the help of FT-IR, NMR, UV, Raman, GC–mass spectroscopy, and elemental analysis. The physicochemical properties of gel differ considerably from their corresponding parent metal alkoxides. Hence, the gel can be considered as an immediate precursor for the preparation of functional metal oxide nanomaterials under mild conditions with control over particle size and its distribution, surface chemistry, and particle agglomeration. The morphology of the metal oxides strongly depends on the nature of the precursor and as well as synthetic methodology.

Colloidal titania particles with nanosize size distribution were prepared via sol-gel process by using oxo-titanium alkoxide as a molecular precursor. The transformation from oxo-titanium alkoxide to metal oxide was studied by IR, UV, thermal analysis, X-ray and TEM. TEM and XRD techniques were used to characterize the microstructure and crystallite morphology. The experimental results show that the titania has a good crystallinity with a particle size (5 nm), shape and with favorable surface morphology. These results support that titania has strong implications for the interaction between the oleic acid used as surfactant and Ti nanoparticle to enhance the stability with controlled functional properties.

Nanocrystalline Bi 4 Ti 3 O 12 powder of high phase purity was produced by the intense mechanical activation of a mixture of α-Bi 2 O 3 and TiO 2 (rutile). The oxides mixture was converted initially to a sillenite (Bi 12 TiO 20 ) phase and then to a crystalline Bi 4 Ti 3 O 12 phase through the gradual disappearance of rutile. The formation of Bi 4 Ti 3 O 12 was complete after a milling time of 9 h. Mechanical alloying occurred between rutile and the more ductile Bi 2 O 3 phase, which resulted in the formation of sillenite. The sillenite was found to be a solid solution with a concentration higher than the stoichiometric amount of Ti. The occurrence of sillenite led to the complete formation of the final Bi 4 Ti 3 O 12 phase within a short milling time.

Due to dynamic and infrastructure-less nature of Mobile Ad hoc Network (MANET) environment, there exist number of threats as mobile devices and nodes could freely move around in MANET such as eavesdropping of communications channels, modification of sensitive m-commerce transactions, Denial of Service(DoS), vulnerabilities of impersonation by malicious insiders etc. In this paper, we propose a novel authenticated group key agreement protocol for end-to-end security in the MANET environment without any infrastructure that is based on Burmester and Desmedt group key agreement protocol (Burmester M, Desmedt Y. A secure and efficient conference key distribution system. Advances in Cryptology - EuroCrypt '94, Lecture Notes in Computer Science 1995;950:275-86) and their variants (Choi KY, Hwang JY, Lee DH. Efficient ID-based group key agreement with bilinear maps. Public Key Cryptography - PKC, Lecture Notes in Computer 2004;2947:130-144)]. We also design practical enhancements of BD and Choi et al.'s protocols that not only detect, but also identify malicious insiders by using the trusted arbiter who only involves in the protocol if the cheating has been occurred.

Crystalline Nd-substituted Bi4Ti3O12 (BNT) nanopowder was directly produced from a stoichiometric oxide mixture by intense milling. During the milling, mechanical alloying between the constituent oxides occurred, resulting in a sequential phase transformation from metastable fluorite to BNT with increasing milling time. The formation of the BNT phase was complete after 9 h of milling. The resulting powder consisted of nearly monodisperse crystallites of ∼18 nm average size, exhibiting a zeta potential of +50 mV at pH ∼ 2.

In this study, we prepared zirconia gel by the sol-gel method and investigated its photoluminescence properties by varying pyrolysis temperature. The addition of acetic acid into a Zr-alkoxide solution resulted in forming the bidentate ligands with Zr ions and producing a stable gel. At the pyrolysis temperature of 350℃, the zirconia nanocrystals with tetragonal structure gradually appeared in the gel. The PL intensity of the zirconia gel increased with increasing the pyrolysis temperature up to 350℃, but decreased above the temperature. Concurrently, its PL peak wavelength continuously shifted from ~440 nm to ~550 nm with the temperature. The PL characteristics of the zirconia gels were closely associated with decomposition of residual organic groups, the formation of the zirconia nanocrystals, and the tetragonal to monoclinic phase transformation.

We report the observation of the carbon nanostructures simply obtained from the sol-gel process using zirconium alkoxide with subsequent heat-treatment. A Raman study showed that the well-defined D and G active modes in multi-walled carbon nanotube similarly appeared in the sample prepared at 350 and 400 . Those disappeared when the sample was heat-treated above 450 , at which its phase fully transformed to zirconia. We observed through HRTEM that either sphere or tube-like carbon nanostructure appeared dispersedly or in a cluster among the oxide aggregates at 350 and 400 . Our study demonstrated that both of the two carbon nanostructures occurred in an intermediate related to carbonization, which may exist during the heat-treatment even in air

We developed a process for coating CuO powder with magnetite film from an aqueous solution. Reaction solution contained 0.12 M of FeCl2 and 0.03 M of CuCl2. The Cu2+ ions promoted the oxidation of Fe(OH)2 to form Fe3O4. The solution was maintained at pH ∼6 using CH3COONH4 of 0.2 M as a buffer to prevent the formation of hematite. The CuO grains of a spherical shape and ∼50 μm in size were mechanically suspended in the solution, on which magnetite particles were directly deposited. The mole ratio of Cu2+ / Fe2+ strongly influenced the coverage of the magnetite film as well as the morphology of the constituent grains. When the Fe2+ / Cu2+ mole ratio was 1: 0.5, the spherical magnetite particles of ∼60 nm in diameter coated well each CuO grain with the thickness of ∼3 μm. The prepared powder exhibited that the saturation magnetization and the coercivity reached to ∼5.4 emu/g and ∼575 Oe, respectively. On heating up to 450 °C, the powder experienced two oxidations below 400 °C, indicating the formation of γ-Fe2O3. The magnetic composite powder appeared to be stable up to 400 °C. (© 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Recent advances in in-vehicle technologies have paved way to a new era of connectivity. Vehicle manufacturers have already deployed various technologies for driving assistance, anti-theft, and infotainment. They are now developing ways to interface mobile devices with vehicles and provide the customer's smart phone or tablet the ability to send/receive information to/from the car. However, such an integration introduces severe security risks to the vehicle. The in-vehicle network was originally designed to operate in a closed environment and thus, security was not of concern. It has now become an important issue due to an increasing number of external interfaces to the in-vehicle network. Several studies have already shown that an in-vehicle network can be easily compromised just by connecting cheap commercial devices and doing reverse engineering. Although research efforts have been made to secure in-vehicle networks, most of them focused on defining security requirements, or presenting attack scenarios without providing any feasible solution. Also, to the best of our knowledge, there hasn't been any study with a specific focus on understanding and analyzing the security aspects of integrating mobile devices with cars. In this paper, we define the integration model, present the attack scenarios, define the security objectives, and then propose a 3-step verification mechanism that meets our objectives.

In this paper, we enhance our untraceable mobile sensor node protocol (Han K, Kim K, Shon T (2010) Sensors 10(5):4410–4429) that reduce computation overhead, and also satisfies practical security strength.

Convergence environments and technologies are urgently coming close to our life with various wireless communications and smart devices in order to provide many benefits such as connectivity, usability, mobility, portability, and flexibility as well as lower installation and maintenance costs. Convergence has brought important change not only in the way we live but also in the way we think. It is the progress towards the attempt to create and to evolve new valuable services through the device convergence and fusion of in-home, office, and various environments around the personal mobile apparatus. Based on the dynamic trends of convergence, it is widely argued that the increased requirements on secure and robust connectivity between a variety of mobile devices and their applications provide us the era of real pervasive computing environment. Thus, in this paper, we present a novel connectivity architecture using RF4CE-(Radio Frequency for Consumer Electronics-) based wireless zero-configuration and enhanced key agreement approach. We analyze the security and performance of our proposed approach by the development of the prototype H/W and the construction of a testbed with CE and mobile devices.

For the lawful interception (LI) of the secure communications, ID-based cryptosystem has the property of key escrow that can be efficiently used for LI. However, it does not prevent the malicious use of the escrowed key by the LEA. Thus, we would like to propose a new key escrow model that enables the limited capability of lawful interception agency.

SIP (session initiation protocol) [1] is widely used in Internet as a signaling protocol for VoIP (voice over IP) and multimedia services. Recently, there have been some efforts to propose peer-to-peer SIP (P2P-SIP) architecture, which makes use of a peer-to-peer network instead of registrar and location SIP servers in order to facilitate SIP user registration and location. One of main issues in P2P-SIP is authentication of resource such as SIP user information without an authentication server. In order to authenticate the resources in P2P-SIP, the signature can be attached to the end of SIP message under PKI (Public Key Infrastructure) framework. However, the PKI-based signature model in P2P-SIP requires verification of central authorities (CA) during SIP message routing and certificates maintenance of intermediate nodes for authentication procedure. It causes much delay in signaling as users increase in P2P-SIP. Especially, much delay in signaling of real-time multimedia communication can be a significant problem. In this paper, we propose an efficient resource registration and location scheme in P2P-SIP, using ID-based signature which has more light-weight authentication procedures. ID-based cryptography is firstly proposed in [2], which is signature scheme, based on the bilinear pairings on elliptic curves. ID-based signature allows users to verify digital signatures using only public information such as the user's identity, while PKI-based signature requires verification of each user's public key from CAs. It can utilize public identifier such as e-mail ID or SIP-URI as a public key, so that it reduces the complexity and costs for establishing and managing the public key of nodes. In this paper, we identify efficiency of this resource registration and location scheme, using ID-based signature in comparison with PKI-based signature model through simulation.

In this paper, an enhanced lightweight identity authentication protocol for access control in IEEE 802.11 networks are presented. The proposed protocol is nicely integrated with the current MAC frame structure and takes the most advantage of the redundancy bits inside the MAC frame header to convey the authentication information, as well as the synchronization information in case of synchronization loss happening. A much more efficient and fault-tolerant synchronization algorithm is given at the same time, which significantly improved the performance of the proposed protocol as compared to the previous ones. The proposed protocol is highly effective as evaluated via a thorough mathematical analysis. A quantitative attack detection framework is also established based on the evaluation result. Finally, the proposed protocol is well suited in a wireless constrained environment for its low communication and computation overheads, requiring only several additional bits (less than 8) for transmission and random bit generating operation.