Changhai Ou

Nanyang Technological University | ntu

First-mile transportation provides convenient transit service for passengers to travel from their homes, workplaces, or public institutions to a public transit station that is located beyond comfortable walking distance. This paper studies the Passenger-Centric Vehicle Routing for First-Mile Transportation (PCVR-FMT) problem to plan optimal vehicle...

An accurate leakage model is critical to side-channel attacks and evaluations. Leakage certification plays an important role to address the following question: “how good is my leakage model?” Moreover, most of the current leakage model profiling only exploits the information from lower orders of moments. They still need to tolerate assumption error...

Recovering keys ranked in very deep candidate space efficiently is a very important but challenging issue in Side-Channel Attacks (SCAs). State-of-the-art Collision-Optimized Divide-and-Conquer Attacks (CODCAs) extract collision information from a collision attack to optimize the key recovery of a divide-and-conquer attack, and transform the very h...

With the explosive development of pervasive computing and the Internet of Things (IoT), indoor positioning and navigation have attracted immense attention over recent years. Pedestrian dead reckoning (PDR) is a potential autonomous localization technology that obtains the position estimation employing built-in sensors. However, most existing PDR me...

Several combined attacks have shown promising results in recovering cryptographic keys by introducing collision information into divide-and-conquer attacks to transform a part of the best key candidates within given thresholds into a much smaller collision space. However, these Collision-Optimized Divide-and-Conquer Attacks (CODCAs) uniformly demar...

Transport mode identification (TMI), which infers the travel modes of user trajectories, is essential to facilitate an understanding of urban mobility patterns and passengers' choice behaviors with the goal of improving urban transportation systems. To achieve higher accuracy, existing TMI methods usually rely on mobility features obtained from den...

By introducing collision information into divide-and-conquer attacks, several existing works transform the original candidate space, which may be too large to enumerate, into a significantly smaller collision space, making key recovery possible. However, the use of inefficient collision detection algorithms and fault tolerance mechanisms make them...

The ability to accurately estimate a user’s stride-length plays a great important role in various applications. For a new target pedestrian or device, their heterogeneity dramatically reduces the performance of the current stride-length estimation methods. To address the issue of heterogeneity, in this paper, we propose a stride-length estimation m...

An important prerequisite for Side-Channel Attacks (SCA) is leakage sampling where the side-channel measurements (i.e. power traces) of the cryptographic device are collected for further analysis. However, as the operating frequency of cryptographic devices continues to increase due to advancing technology, leakage sampling will impose higher requi...

Accurate heading estimation is the foundation of numerous applications, including augmented reality, pedestrian dead reckoning, and human-computer interactions. While magnetometer is a key source of heading information, the poor accuracy of consumer-grade hardware coupled with the pervasive magnetic disturbances makes accurate heading estimation a...

Integrity trees are widely used in computer systems to prevent replay, splicing, and spoofing attacks on memories. Such mechanisms incur excessive performance and energy overhead. We propose a memory authentication framework that combines architecture-specific optimizations of the integrity tree with mechanisms that enable it to restructure at runt...

Stride length and walking distance estimation are becoming a key aspect of many applications. One of the methods of enhancing the accuracy of pedestrian dead reckoning is to accurately estimate the stride length of pedestrians. Existing stride length estimation (SLE) algorithms present good performance in the cases of walking at normal speed and th...

Key enumeration schemes are used to post-process the scores given by side channel distinguishers and enumerate the key candidates from the most possible one to the least possible one, which can be regarded as optimal tools of key search. However, the application of them is limited by very large key candidate space and computing power consumption. F...

Customer’s product preference provides how a customer collects products or prefers one collection over another. Understanding customer’s product preference can provide retail store owner and librarian valuable insight to adjust products and service. Current solutions offer a certain convenience over common approaches such as questionnaire and inter...

In the context of side channel attacks (SCA), multiple preprocessing methods proposed are used to improve the quality of measurements and enhance the attack performance. Different from existing preprocessing methods which accord to the spectral distribution of noise or depend on some objective functions to search optimal linear transform, we treat...

Bogdanov and Kizhvatov proposed the concept of test of chain, but they didn’t give a practical scheme. Wang et al. proposed fault tolerant chain to enhance test of chain and gave a practical scheme. However, the attack efficiency of Correlation enhanced Collision Attack (CCA) is much lower than that of Correlation Power Analysis (CPA). A combinatio...

Biasing power traces with high Signal to Noise Ratio (SNR) proposed by K. Yongdae et al. can significantly improve the efficiency of the CPA. But it is still a problem to be solved that how to efficiently select power traces with high SNR. Through the analysis of the statistical characteristics of power traces, we propose three methods to better so...

Correlation enhanced Collision Attacks (CCA) can be able to exploit any first-order leakage without knowing the precise hypothetical power model. However, the correlation between time samples of two S-boxes is relatively weak, which leads to the low efficiency of CCA. Actually, the efficiency of CCA is much lower than that of Correlation Power Anal...

In side channel attacks (SCA), noise has been a hot topic for affecting the quality of obtained observations. In this paper, we propose a kind of improved wavelet transform denoising method based on singular spectral analysis (SSA) and detrended fluctuation analysis (DFA). Principal signal component in SSA can be selected by DFA adaptively, and res...

Electromagnetic analysis in side channel attack exploits the information of electromagnetic radiation that leaks from the cryptographic devices when they are running. It's no-table because of its efficiency and easiness to perform. Correlation electromagnetic analysis (CEMA) is of the most effective means in electromagnetic analysis. However, the e...

The efficiency can be significantly improved if the attacker uses interesting points to perform Correlation Power Analysis (CPA). The prerequisite for this is that the attacker knows the positions of interesting points. However, it is difficult for the attacker to accurately find the locations of interesting points if he only has a small number of...

It has always been the concern of side channel analysis that how to recover the key with a probability of about 1.00 under the condition that the number of power traces is very small and the success rates is very low. In order to recover the key, the attacker has to try to reduce the guessing entropy to decrease the uncertainty of the key. Unfortun...

Correlation Power Analysis (CPA) is one of effective means of power analysis in side channel analysis. The noisy power traces can affect the power of CPA. It is significant to select the helpful power traces to improve the efficiency of analysis. In this paper, we present a new pre-processing method that is based on Improved Singular Value Decompos...