In this letter, we propose a secrecy criterion for outsourcing encrypted databases. In encrypted databases, encryption schemes revealing some information are often used in order to manipulate encrypted data efficiently. The proposed criterion is based on inference analysis for databases: We simulate attacker's inference on specified secret information with and without the revealed information from the encrypted database. When the two inference results are the same, then secrecy of the specified information is preserved against outsourcing the encrypted database. We also show that the proposed criterion is decidable under a practical setting.

A rotating shaft with attached sensors is wrapped in a two-dimensional waveguide sheet through which the data and power are wirelessly transmitted. A retrodirective transponder array affixed to the sheet beamforms power to the moving sensor to eliminate the need for a battery. A universal on-sheet reference scheme is proposed for calibrating the transponder circuit delay variation and eliminating a crystal oscillator from the sensor. A base signal transmitted from the on-sheet reference device is used for generating the pilot signal transmitted from the sensor and the power signal transmitted from the transponder. A 0.18-µm CMOS transponder chip and the sheet with couplers were fabricated. The coupler has three resonant frequencies used for the proposed system. The measured propagation gain of the electric field changes to less than ±1.5dB within a 2.0-mm distance between the coupler and the sheet. The measured power transmission efficiency with beamforming is 23 times higher than that without it. Each transponder outputs 1W or less for providing 3mW to the sensor.

In this paper, Proxy Mobile IPv6 (PMIPv6), which is a network-based mobility management protocol, is adapted to the OpenFlow architecture. Mobility-related signaling is generally performed by network entities on behalf of a mobile node, but in standard PMIPv6, the control and data packets are delivered and processed over the same network entities, which prevents the separation of the control and the data planes. In addition, IP tunneling inherent to PMIPv6 imposes excessive overhead for the network entities. In order to adapt PMIPv6 to the OpenFlow architecture, the mobility management function is separated from the PMIPv6 components, and components are reconstructed to take advantage of the offerings of the OpenFlow architecture. The components configure the flow table of the switches located in a path, which comprise the OpenFlow controller. Mobility-related signaling can then be performed at the dedicated secure channel, and all of the data packets can be sent normally in accordance with the flow table of the OpenFlow switches. Consequently, the proposed scheme eliminates IP tunneling when user traffic is forwarded and separates the data and the control planes. The performance analysis revealed that the proposed scheme can outperform PMIPv6 in terms of the signaling cost, packet delivery cost, and handover latency.

We investigated client honeypots for detecting and circumstantially analyzing drive-by download attacks. A client honeypot requires both improved inspection performance and in-depth analysis for inspecting and discovering malicious websites. However, OS overhead in recent client honeypot operation cannot be ignored when improving honeypot multiplication performance. We propose a client honeypot system that is a combination of multi-OS and multi-process honeypot approaches, and we implemented this system to evaluate its performance. The process sandbox mechanism, a security measure for our multi-process approach, provides a virtually isolated environment for each web browser. It prevents system alteration from a compromised browser process by I/O redirection of file/registry access. To solve the inconsistency problem of file/registry view by I/O redirection, our process sandbox mechanism enables the web browser and corresponding plug-ins to share a virtual system view. Therefore, it enables multiple processes to be run simultaneously without interference behavior of processes on a single OS. In a field trial, we confirmed that the use of our multi-process approach was three or more times faster than that of a single process, and our multi-OS approach linearly improved system performance according to the number of honeypot instances. In addition, our long-term investigation indicated that 72.3% of exploitations target browser-helper processes. If a honeypot restricts all process creation events, it cannot identify an exploitation targeting a browser-helper process. In contrast, our process sandbox mechanism permits the creation of browser-helper processes, so it can identify these types of exploitations without resulting in false negatives. Thus, our proposed system with these multiplication approaches improves performance efficiency and enables in-depth analysis on high interaction systems.

A novel ROI-based reversible data hiding scheme is proposed for medical images, which is able to hide electronic patient record (EPR) and protect the region of interest (ROI) with tamper localization and recovery. The proposed scheme combines prediction error expansion with the sorting technique for embedding EPR into ROI, and the recovery information is embedded into the region of non-interest (RONI) using histogram shifting (HS) method which hardly leads to the overflow and underflow problems. The experimental results show that the proposed scheme not only can embed a large amount of information with low distortion, but also can localize and recover the tampered area inside ROI.

A proxy signature scheme allows an entity to delegate his signing capabilities to another. Many schemes have been provided for use in numerous applications such as distributed computing, grid computing, and mobile communications. In 2003, Boldyreva et al. introduced the first formal security model of proxy signatures and also proposed a generic construction secure in their model. However, an adversary can arbitrarily alter the warrants of the proxy signatures because the warrants are not explicitly considered in their model. To solve this problem, Huang et al. provided an enhanced security model of proxy signatures in 2005. Some proxy signatures secure in this security model have been proposed but there is no generic construction yet. In this paper, we redefine and improve the Huang et al.'s security model in terms of multi-user and then provide a new generic construction of proxy signatures secure against our enhanced security model based on ID-based signatures. Moreover, we can make a lattice-based proxy signature scheme in the standard model from our result.

Accessing a geo-location database is one of the approaches for a secondary user (SU) to obtain the list of available channels for its operation. Channel availability is calculated based on information stored in the geo-location database and information submitted by the SU so that primary users (PU) are protected from harmful interference. The available channel checking process is modeled as a number of intersection tests between the protected contours of PUs and the operation area of the SU regarding to all potential channels. Existing studies indicated that these intersection tests consume time and introduce overhead to the database, especially when the contours or the operation areas are represented by n-polygons and the number of vertices n is a large number. This paper presents a novel method of determining available channels which reduces the number of intersection tests. By submitting SU's preferred channels or the number of channels to be checked to the database, the calculation time and database's load will be reduced significantly. This paper also presents analysis and simulation results of the database workload and the average number of channels obtained per query on different query methods. Suitable query method can be selected based on the number of similar channels in neighbor areas and the maximum number of intersection tests.

A new exemplar-based inpainting method which effectively preserves global structures and textures in the restored region driven by feature vectors is presented. Exemplars that belong to the source region are segmented based on their features. To express characteristics of exemplars such as shapes of structures and smoothness of textures, the Harris corner response and the variance of pixel values are employed as a feature vector. Enhancements on restoration plausibility and processing speedup are achieved as shown in the experiments.

How to retrieve the closest content from an in-network cache is one of the most important issues in Information-Centric Networking (ICN). This paper proposes a novel content discovery scheme called Local Tree Hunting (LTH). By adding branch-cast functionality to a local tree for content requests to a Content-Centric Network (CCN) response node, the discovery area for caching nodes expands. Since the location of such a branch-casting node moves closer to the request node when the content is more widely cached, the discovery range, i.e. the branch size of the local tree, becomes smaller. Thus, the discovery area is autonomously adjusted depending on the content dissemination. With this feature, LTH is able to find the “almost true closest” caching node without checking all the caching nodes in the in-network cache. The performance analysis employed in Zipf's law content distribution model and which uses the Least Recently Used eviction rule shows the superiority of LTH with respect to identifying the almost exact closest cache.

This paper discusses the decidability of node query preservation problems for tree transducers. We assume a transformation given by a deterministic linear top-down data tree transducer (abbreviated as DLTV) and an n-ary query based on runs of a tree automaton. We say that a DLTV Tr strongly preserves a query Q if there is a query Q' such that for every tree t, the answer set of Q' for Tr(t) is equal to the answer set of Q for t. We also say that Tr weakly preserves Q if there is a query Q' such that for every t, the answer set of Q' for Tr(t) includes the answer set of Q for t. We show that the weak preservation problem is coNP-complete and the strong preservation problem is in 2-EXPTIME. We also show that the problems are decidable when a given transducer is a functional extended linear top-down data tree transducer with regular look-ahead, which is a more expressive transducer than DLTV.

Presently, many identity-based proxy signature (IBPS) schemes have been proposed, but most of them require high computational costs and the proposed security model for IBPS is not enough complete. To overcome this weakness, Gu et al. recently proposed a framework and a detailed security model for IBPS. They also proposed an efficient IBPS scheme and proved the unforgeability of their scheme in the standard model. However, in this letter, we demonstrate that Gu et al.'s scheme fails to satisfy the property of unforgeability because it can not resist the following attacks: after getting a private key, an adversary behaving as a malicious signer can forge a private key on any identity without the help of the private key generator (PKG); after getting a delegation, an adversary behaving as a malicious proxy signer can forge a proxy signing key on any delegation without the agreement of the original signer; after getting a signature, an adversary behaving as a malicious user can forge a signature on any identity without the private key or forge a proxy signature on any warrant without the proxy signing key.

We propose that the current distribution along a dipole can be divided into a component proportional to the port current, a component proportional to the port voltage, and an antisymmetrical component. In this paper, we perform numerical computations to verify that the component proportional to the port voltage always lags the port voltage by 90°, and the ratio of its amplitude to that of the port voltage is not significantly affected by the arrangement of other dipoles located nearby or by circuits connected to the ports of the dipoles if the dipoles have lengths not exceeding one wavelength.

A serial ATA PHY fabricated in a 0.15-µm CMOS process performs the serial ATA operation in an asynchronous transition by using large variation in the reference clock. This technique calibrates a transmission signal frequency by utilizing the received signal. This is achieved by calibrating the divide ratio of a spread-spectrum clock generator (SSCG). This technique enables a serial ATA PHY to use reference oscillators with a production-frequency tolerance of less than 400ppm, i.e., higher than the permissible TX frequency variations (i.e., 350ppm). The calibrated transmission signal achieved a total jitter of 3.9ps.

The concept of dual pairing vector spaces (DPVS) was introduced by Okamoto and Takashima in 2009, and it has been employed in various applications, functional encryption (FE) including attribute-based encryption (ABE) and inner-product encryption (IPE) as well as attribute-based signatures (ABS), generic conversion from composite-order group based schemes to prime-order group based ones and public-key watermarking. In this paper, we show the concept of DPVS, the major applications to FE and the key techniques employed in these applications. This paper presents them with placing more emphasis on plain and intuitive descriptions than formal preciseness.

RC4 is a widely-used stream cipher, adopted in many standard protocols, such as WEP, WPA and SSL/TLS, as a standard encryption algorithm. Isobe et al. proposed a plaintext recovery attack on RC4 in the broadcast setting, where the same plaintext is encrypted with different secret keys. Their attack is able to recover the first 257bytes by exploiting the biases of the initial bytes of a keystream. In this paper, we propose two types of full plaintext recovery attacks that are able to recover all the bytes, even after the 258th byte, of a plaintext, unlike Isobe et al.'s attack. To achieve this, we combine the use of multiple keystream biases appropriately. The first attack utilizes the initial byte biases and Mantin's long-term bias. This attack can recover the first 1000 terabytes of a plaintext from 234 ciphertexts with a probability of almost one. The second attack is based on two long-term biases. Since this attack does not rely on the biases of the initial bytes of the RC4 keystream, it can recover any byte of a plaintext, even if the initial bytes are disregarded. Given 235 ciphertexts encrypted by different keys, any byte of a target plaintext can be recovered with a probability close to one.

This paper presents a novel signal analysis algorithm, named High-order Bi-orthogonal Fourier Transform (HBFT), which can be seen as an expansion of Fourier transform. The HBFT formula and discrete HBFT formula are derived, some of their main characteristics are briefly discusses. This paper also uses HBFT to analyze the multi-LFM signals, obtain the modulate rate parameters, analyze the high dynamic signals, and obtain the accelerated and varying accelerated motion parameters. The result proves that HBFT is suitable for analysis of the non-stability signals with high-order components.

A monolithic frequency synthesizer with wide tuning range, low phase noise and spurs was realized in 0.13,$mu$m CMOS technology. It consists of an analog PLL, a harmonic-rejection mixer and injection-locked frequency doublers to cover the whole 6--18,GHz frequency range. To achieve a low phase noise performance, a sub-sampling PLL with non-dividers was employed. The synthesizer can achieve phase noise $-$113.7,dBc/Hz@100,kHz in the best case and the reference spur is below $-$60,dBc. The core of the synthesizer consumes about 110,mA*1.2,V.

In this paper, we consider synchronization phenomena in coupled systems of piecewise constant oscillators. Both in-phase and anti-phase synchronization phenomena are observed in the oscillators, which are coupled by a voltage controlled current source (VCCS) with Signum-like characteristic. On the other hand, their co-existence is observed in the oscillators coupled by a VCCS with hysteresis characteristic. We analyze the stability of the synchronization phenomena in the coupled systems by using a fast calculation algorithm for the rigorous solutions. And we clarify the parameter regions of in-phase and anti-phase synchronization by deriving correlation coefficients. We suggest that the synchronization phenomena of the proposed systems qualitatively correspond to one of van der Pol oscillators coupled by passive elements. Some theoretical results are verified in the experimental circuits.

Yajima et al. proposed a method based on amplitude and phase coding of audio signals. This method has relatively high sound quality because human auditory property is considered for embedding. However, in this method, the tolerance to attacks tends to be weak. Hence, we propose a high-tolerance watermarking method using BCH code which is one of error correcting code. This paper evaluates whether our method preserves the sound quality while ensuring high tolerance.

We propose a novel phased array-fed dual-reflector antenna that reduces performance degradation caused by multiple reflection. The marked feature of the proposed configuration is that different reflector profiles are employed for the two orthogonal directions. The reflector profile in the beam-scanning section (vertical section) is set to an imaging reflector configuration, while the profile in the orthogonal non-beam-scanning section (horizontal section) is set to a ring-focus Cassegrain antenna configuration. In order to compare the proposed antenna with the conventional antenna in which multiple reflection was problematic, we designed a prototype antenna of the same size, and verified the validity of the proposed antenna. The results of the verification were that the gain in the designed central frequency increased by 0.4 dB, and the ripple of the gain frequency properties that was produced by multiple reflection was decreased by 1.1,dB. These results demonstrated the validity of the proposed antenna.