Unmanned Vehicles (UVs) have been being utilized for various applications, such as surveillance, search/rescue, and monitoring. The information they transmit is critical for decision-making. However, UVs are vulnerable to white-box attacks due to improvements in reverse engineering techniques and the openness of their software. Therefore, attackers with sufficient knowledge of a target UV can steal secret information stored in the UV by exploiting its vulnerabilities. Recently, several white-box cryptography techniques have been introduced to protect secret keys from being extracted by converting them into large look-up tables. However, none of them provide approaches to securely update the look-up tables. Thus, once a remote attacker succeeds in extracting the static look-up table from a UV, he/she can use it to decrypt past/future communications or to send false information to the control station by impersonating the UV. In this paper, we propose a look-up table shuffling mechanism that supports white-box cryptography with dynamics. The mechanism makes it hard for attackers to determine the positions of the table entries, and thus to decrypt/encrypt ciphertexts/plaintexts. To show the practicality of the block cipher with our mechanism, we implemented it on a board equipped with a GPU and show its GPU-accelerated performance.

Many localization techniques for wireless sensor networks have been proposed to estimate sensor positions even when there is malicious location information which distorts the estimate. Some of those solutions efficiently estimate sensor positions using the Minimum Mean Square Estimation methods and the Degree-Of-Consistency (DOC). Although such solutions can filter out most of malicious information, if an attacker knows the position of the target sensor, the attacker can significantly alter its estimated position. In this paper, we introduce two attacks based on the knowledge of target sensor positions. The first attack, called Aligned-Beacon-Position (ABP) attack, exploits beacon nodes that are aligned in a line. The second attack, called inside-attack, disables the DOC filtering algorithm by placing malicious location references inside benign location references. To protect against those two known sensor position attacks, we introduce two defense schemes. First, we propose a novel beacon placement strategy to protect against ABP attacks. Second, we present a filtering technique that can filter out malicious location references introduced by inside-attacks. Finally, we propose a localization algorithm which has enhanced accuracy and efficiency compared with previous algorithms. We assess the impact of those attacks and the performance of our defense schemes by simulation and test-bed experiments.

In many envisioned IoT applications, security is crucial. However, designing and/or deploying existing security techniques in IoT systems is not straightforward due to the inherent heterogeneity of IoT devices as well as their huge number. A critical security building block is represented by the Public Key Infrastructure (PKI) relying on Certificate Authorities (CAs). However, even a single-point-of-failure in a PKI may affect entire IoT systems due to its centralized nature. Failures have far reaching effects as the number of IoT devices increases. Furthermore, it is difficult for the owners of IoT devices to manage the certificates for their IoT devices since there are no standard protocols for retrieving, installing and updating the certificates. As a result, IoT device manufacturers often install certificates on the devices on behalf of the owners of the devices, which introduces the risk that the private keys of the devices are leaked by the manufacturers. In this paper, we propose a decentralized PKI for IoT, called IoT-PKI, which utilizes distributed nodes in a blockchain network instead of CAs, and thus addresses scalability. IoT-PKI protects against key leakages at device manufacturers since it allows the owners of IoT devices to manage the certificates of their IoT devices. Finally, we show the feasibility and efficiency of IoT-PKI through our prototype implementation and experiments.

Drones are increasingly being used as mobile data collectors for various monitoring services. However, since they may move around in unattended hostile areas with valuable data, they can be the targets of malicious physical/cyber attacks. These attacks may aim at stealing privacy-sensitive data, including secret keys, and eavesdropping on communications between the drones and the ground station. To detect tampered drones, a code attestation technique is required. However, since attestation itself does not guarantee that the data in the drones' memory are not leaked, data collected by the drones must be protected and secret keys for secure communications must not be leaked. In this paper, we present a solution integrating techniques for software-based attestation, data encryption and secret key protection. We propose an attestation technique that fills up free memory spaces with data repositories. Data repositories consist of pseudo-random numbers that are also used to encrypt collected data. We also propose a group attestation scheme to efficiently verify the software integrity of multiple drones. Finally, to prevent secret keys from being leaked, we utilize a technique that converts short secret keys into large look-up tables. This technique prevents attackers from abusing free space in the data memory by filling up the space with the look-up tables. To evaluate the integrated solution, we implemented it on AR.Drone and Raspberry Pi.

Smart cities aim to improve the quality of urban services and their energy efficiency by utilizing information and communication technologies. In such context, drones can be utilized to support various services, such as traffic monitoring, search/rescue, and surveillance, by communicating with many different smart objects like sensors. Securing such communications is crucial to making correct decisions and requires efficient cryptographic protocols. However, the design of such protocols must consider: 1) the mobility and the limited battery of drones and 2) the constrained resources of smart objects. In this paper, a suite of cryptographic protocols is presented to deal with three different communication scenarios: one-to-one, one-to-many, and many-to-one. For one-to-one, we propose an efficient Certificateless Signcryption Tag Key Encapsulation Mechanism (eCLSC-TKEM) that supports authenticated key agreement, non-repudiation, and user revocation. eCLSC-TKEM reduces the time required to establish a shared key between a drone and a smart object by minimizing the computational overhead at the smart object. For one-to-many, we propose a Certificateless Multi-Recipient Encryption Scheme (CL-MRES) by which a drone can efficiently send privacy-sensitive data to multiple smart objects. For many-to-one, we present a Certificateless Data Aggregation (CLDA) protocol, which allows drones to efficiently collect data from hundreds of smart objects. Also, for efficiency, we propose a dual channel strategy that allows many smart objects to concurrently execute our protocols. We evaluate eCLSC-TKEM via a smart parking management test-bed. Also, we have implemented CL-MRES and CLDA on a board with a graphics processing unit (GPU) and show their GPU-accelerated performance.

Data-driven techniques for agriculture can help farmers reduce waste, increase farm output and ensure sustainability for the environment. The key enabler for such techniques is an always-on connected IoT system that can sense the different characteristics of the farm and generate short-term and long-term actionable insights for the farmer. Yet building such a system is very challenging due to sparse Internet connectivity and lack of reliable power sources. This is further exacerbated by weather variability that stresses the system in numerous ways. We discuss how we built and deployed Farmbeats [6] in the face of these challenges. We hope our experiences will aid researchers who are beginning to explore deployments in farming or other weakly connected, power-starved scenarios, such as construction, oil fields, mining, and others.

Assured Mission Delivery Network (AMDN) is a collaborative network to support data-intensive scientific collaborations in a multi-cloud environment. Each scientific collaboration group, called a mission, specifies a set of rules to handle computing and network resources. Security is an integral part of the AMDN design since the rules must be set by authorized users and the data generated by each mission may be privacy-sensitive. In this paper, we propose a CertificateLess cryptography-based Rule-management Protocol (CL-RP) for AMDN, which supports authenticated rule registrations and updates with non-repudiation. We evaluate CL-RP through test-bed experiments and compare it with other standard protocols.

Data-driven techniques help boost agricultural productivity by increasing yields, reducing losses and cutting down input costs. However, these techniques have seen sparse adoption owing to high costs of manual data collection and limited connectivity solutions. In this paper, we present FarmBeats, an end-to-end IoT platform for agriculture that enables seamless data collection from various sensors, cameras and drones. FarmBeats's system design that explicitly accounts for weather-related power and Internet outages has enabled six month long deployments in two US farms.

Certificateless Signcryption Tag Key Encapsulation Mechanism (CLSC-TKEM) is an effective method for simultaneously providing key encapsulation and a digital signature on the tag. It has applications in several security services such as communication confidentiality, integrity, authentication, and non-repudiation. Moreover, because CLSC-TKEM is based on certificateless public key cryptography (CL-PKC), it has the advantage of not requiring public key certificates. In addition it does not suffer from the key escrow problem which is instead a major drawback of identity-based public key cryptography (ID-PKC). Unfortunately, current constructions of CLSC-TKEM rely on the use of bilinear pairing-based operations that are computationally very expensive for small IoT devices. In this paper, we present a new construction of CLSC-TKEM that does not require bilinear pairing operations. We refer to our new construction on pairing-free Certificateless Signcryption Tag Key Encapsulation Mechanism (pCLSC-TKEM). We also provide a simple construction for pairingfree certificateless hybrid signcryption by combining pCLSC-TKEM with a data encapsulation mechanism (DEM). We provide a security model for pCLSC-TKEM. Then, we prove that our pCLSC-TKEM is secure against both an adaptively chosen ciphertext attack and existential forgery in the random oracle model. We have implemented our pCLSC-TKEM construction and previous pairing-based CLSC-TKEM constructions in order to compare their performance. Our experimental results demonstrate that pCLSC-TKEM is much more efficient that previous pairing-based CLCS-TKEM constructions.

Delivery drones are unmanned aerial vehicles (UAV) utilized to transport packages, food, medicine, or other goods. With high demand for a prompt and efficient delivery, a drone delivery system can be an effective solution for timely deliveries and especially for emergency management. However, current delivery drone systems lack crucial security functions. Drones may have to operate in unsupervised hostile areas, and therefore be vulnerable to physical capture in addition to conventional cyber attacks. A captured drone can be analyzed by a white-box attack model in which the attacker has full control over the execution environment of cryptographic modules in static and dynamic methods including all side-channel information. In this paper, we propose and evaluate a security framework which utilizes white-box cryptography in order to protect critical data and cryptographic keys in delivery drones from white-box attacks. The experimental results show that the proposed framework is cost effective in terms of resource usage and thus is suitable even for resource-limited UAV.

In many envisioned drone-based applications, drones will communicate with many different smart objects, such as sensors and embedded devices. Securing such communications requires an effective and efficient encryption key establishment protocol. However, the design of such a protocol must take into account constrained resources of smart objects and the mobility of drones. In this paper, a secure communication protocol between drones and smart objects is presented. To support the required security functions, such as authenticated key agreement, non-repudiation, and user revocation, we propose an efficient Certificateless Signcryption Tag Key Encapsulation Mechanism (eCLSC-TKEM). eCLSC-TKEM reduces the time required to establish a shared key between a drone and a smart object by minimizing the computational overhead at the smart object. Also, our protocol improves drone's efficiency by utilizing dual channels which allows many smart objects to concurrently execute eCLSC-TKEM. We evaluate our protocol on commercially available devices, namely AR.Drone2.0 and TelosB, by using a parking management testbed. Our experimental results show that our protocol is much more efficient than other protocols.

Several solutions have recently been proposed to securely estimate sensor positions even when there is malicious location information which distorts the estimate. Some of those solutions are based on the Minimum Mean Square Estimation (MMSE) methods which efficiently estimate sensor positions. Although such solutions can filter out most of malicious information, if an attacker knows the position of a target sensor, the attacker can significantly alter the position information. In this paper, we introduce such a new attack, called Inside-Attack, and a technique that is able to detect and filter out malicious location information.

Recently, wireless sensor networks (WSNs) have been deployed for a wide variety of applications, including military sensing and tracking, patient status monitoring, traffic flow monitoring, where sensory devices often move between different locations. Securing data and communications requires suitable encryption key protocols. In this paper, we propose a certificateless-effective key management (CL-EKM) protocol for secure communication in dynamic WSNs characterized by node mobility. The CL-EKM supports efficient key updates when a node leaves or joins a cluster and ensures forward and backward key secrecy. The protocol also supports efficient key revocation for compromised nodes and minimizes the impact of a node compromise on the security of other communication links. A security analysis of our scheme shows that our protocol is effective in defending against various attacks. We implement CL-EKM in Contiki OS and simulate it using Cooja simulator to assess its time, energy, communication, and memory performance.

Wireless Sensor Networks (WSNs) have been substituting for human senses to make human lives better by monitoring the environment and providing intelligence. Collected sensor data are used to make decisions as a human does. Therefore, providing trustworthy sensor data is crucial to make correct decisions. However, faulty sensors can give incorrect information. In addition, since sensors are usually deployed in unattended areas and can be compromised, cryptographic approaches are insufficient. To address this problem, we propose a distance-based trustworthiness assessment scheme. In our scheme, a centralized trust assessment module outputs an absolute trust score of each sensed value and the trust score of each sensor. The trust scores of sensed values are calculated based on the differences of sensed values provided by a sensor and its neighbors and the physical distances from the neighbors. Our simulation results show that our scheme outputs practical and accurate trust scores in a realistic environment where the sensed values of interest gradually change over the monitored areas.

Smart meters are integral to demand response in emerging smart grids, by reporting the electricity consumption of users to serve application needs. But reporting real-time usage information for individual households raises privacy concerns. Existing techniques to guarantee differential privacy (DP) of smart meter users either are not fault tolerant or achieve (possibly partial) fault tolerance at high communication overheads. In this paper, we propose a fault-tolerant protocol for smart metering that can handle general communication failures while ensuring DP with significantly improved efficiency and lower errors compared with the state of the art. Our protocol handles fail-stop faults proactively by using a novel design of future ciphertexts, and distributes trust among the smart meters by sharing secret keys among them. We prove the DP properties of our protocol and analyze its advantages in fault tolerance, accuracy, and communication efficiency relative to competing techniques. We illustrate our analysis by simulations driven by real-world traces of electricity consumption.

CertificateLess Hybrid SignCryption (CL-HSC) scheme is useful for efficiently encapsulating symmetric keys for secure communications. It solves the key escrow problem and the certificate management problem. However, the existing scheme is not suitable for Advanced Metering Infrastructure (AMI) networks because of the utilization of expensive pairing operations. As smart meter devices have limited computing power, we need efficient algorithms for AMI networks. In this poster, we propose a novel CL-HSC scheme without pairing operations. In order to evaluate its performance, we implemented our CL-HSC scheme and conventional hybrid encryption approaches. The experimental results show that our CL-HSC scheme is efficient and suitable for secure communications in AMI networks.

IEEE 802.11 Wireless LANs support multiple data transmission rates at physical (PHY) layer. Various rate adaptation schemes that select optimal transmission rate according to the receivers' channel condition have been proposed. Among these protocols, Automatic Rate Fallback (ARF) is the one that is widely implemented in commercial devices due to its simplicity. However, it is well-known that the performance of ARF deteriorates when the wireless channel condition is unstable or many frame collisions occur. On the other hand, RBAR (Receiver Based Auto-Rate) that achieves the good performance is rarely used because it introduces extra control overhead. In this paper, we propose a novel rate adaptation scheme that performs well without control overhead. The key idea of our proposed scheme is that if a station successfully overhears a downlink transmission whose data rate is higher than its current rate, then it requests the AP to increase the data rate to overheard frame's transmission rate. We compare our scheme with previous rate adaptation schemes in terms of throughput performance via the simulation study. The performance results indicate that our scheme achieves better performance than RBAR.