34 research outputs found

    State of the Art in Lightweight Symmetric Cryptography

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    Lightweight cryptography has been one of the hot topics in symmetric cryptography in the recent years. A huge number of lightweight algorithms have been published, standardized and/or used in commercial products. In this paper, we discuss the different implementation constraints that a lightweight algorithm is usually designed to satisfy in both the software and the hardware case. We also present an extensive survey of all lightweight symmetric primitives we are aware of. It covers designs from the academic community, from government agencies and proprietary algorithms which were reverse-engineered or leaked. Relevant national (NIST...) and international (ISO/IEC...) standards are listed. We identified several trends in the design of lightweight algorithms, such as the designers\u27 preference for ARX-based and bitsliced-S-Box-based designs or simpler key schedules. We also discuss more general trade-offs facing the authors of such algorithms and suggest a clearer distinction between two subsets of lightweight cryptography. The first, ultra-lightweight cryptography, deals with primitives fulfilling a unique purpose while satisfying specific and narrow constraints. The second is ubiquitous cryptography and it encompasses more versatile algorithms both in terms of functionality and in terms of implementation trade-offs

    Lightweight method of shuffling overlapped data-blocks for data integrity and security in WSNs

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    Wireless Sensor Networks (WSN) consist of devices with limited resources to explore and sense the environment in a cooperative way. Security, mainly in terms of guaranteeing the data integrity, is a primary issue for many applications, but with an extra energy cost. Thus, trade-off is required between security level and energy consumption in real applications. First of all, a brief survey about security methods, focusing in data integrity, in WSN is implemented. The objective of this paper is to propose a new data integrity method with medium security levels and low energy cost. Therefore, we propose a new and lightweight mechanism for data integrity with overlapping blocks in WSNs. Hence, an attacker will spend much time and effort to interpret and alter the packets. The experiments were performed using TinyOS 2.1 operating system and TelosB nodes for measuring the overhead in terms of energy consumption, memory, and packet size. Moreover, the receiver is able to detect tampering packets and request those retransmission data. An attacker would require huge amounts of memory and processing time to extract the original information, even for small-sized data blocks. Thus, this fact makes this approach a simple, yet effective, mechanism to protect data whilst enhancing the data integrity

    Cryptography: Recent Advances and Research Perspectives

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    Cryptography is considered as a branch of both mathematics and computer science, and it is related closely to information security. This chapter explores the earliest known cryptographic methods, including the scytale, Caesar cipher, substitution ciphers, and transposition ciphers. Also, explains the evolution of these methods over time. The development of symmetric and asymmetric key cryptography, hash functions, and digital signatures is also discussed. The chapter highlights major historical events and technological advancements that have driven the need for stronger and more efficient encryption methods. In addition, the chapter explores the potential for integrating artificial intelligence tools with cryptographic algorithms and the future of encryption technology

    Efficient and Secure Implementations of Lightweight Symmetric Cryptographic Primitives

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    This thesis is devoted to efficient and secure implementations of lightweight symmetric cryptographic primitives for resource-constrained devices such as wireless sensors and actuators that are typically deployed in remote locations. In this setting, cryptographic algorithms must consume few computational resources and withstand a large variety of attacks, including side-channel attacks. The first part of this thesis is concerned with efficient software implementations of lightweight symmetric algorithms on 8, 16, and 32-bit microcontrollers. A first contribution of this part is the development of FELICS, an open-source benchmarking framework that facilitates the extraction of comparative performance figures from implementations of lightweight ciphers. Using FELICS, we conducted a fair evaluation of the implementation properties of 19 lightweight block ciphers in the context of two different usage scenarios, which are representatives for common security services in the Internet of Things (IoT). This study gives new insights into the link between the structure of a cryptographic algorithm and the performance it can achieve on embedded microcontrollers. Then, we present the SPARX family of lightweight ciphers and describe the impact of software efficiency in the process of shaping three instances of the family. Finally, we evaluate the cost of the main building blocks of symmetric algorithms to determine which are the most efficient ones. The contributions of this part are particularly valuable for designers of lightweight ciphers, software and security engineers, as well as standardization organizations. In the second part of this work, we focus on side-channel attacks that exploit the power consumption or the electromagnetic emanations of embedded devices executing unprotected implementations of lightweight algorithms. First, we evaluate different selection functions in the context of Correlation Power Analysis (CPA) to infer which operations are easy to attack. Second, we show that most implementations of the AES present in popular open-source cryptographic libraries are vulnerable to side-channel attacks such as CPA, even in a network protocol scenario where the attacker has limited control of the input. Moreover, we describe an optimal algorithm for recovery of the master key using CPA attacks. Third, we perform the first electromagnetic vulnerability analysis of Thread, a networking stack designed to facilitate secure communication between IoT devices. The third part of this thesis lies in the area of side-channel countermeasures against power and electromagnetic analysis attacks. We study efficient and secure expressions that compute simple bitwise functions on Boolean shares. To this end, we describe an algorithm for efficient search of expressions that have an optimal cost in number of elementary operations. Then, we introduce optimal expressions for first-order Boolean masking of bitwise AND and OR operations. Finally, we analyze the performance of three lightweight block ciphers protected using the optimal expressions

    Triathlon of Lightweight Block Ciphers for the Internet of Things

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    In this paper, we introduce a framework for the benchmarking of lightweight block ciphers on a multitude of embedded platforms. Our framework is able to evaluate the execution time, RAM footprint, as well as binary code size, and allows one to define a custom "figure of merit" according to which all evaluated candidates can be ranked. We used the framework to benchmark implementations of 19 lightweight ciphers, namely AES, Chaskey, Fantomas, HIGHT, LBlock, LEA, LED, Piccolo, PRESENT, PRIDE, PRINCE, RC5, RECTANGLE, RoadRunneR, Robin, Simon, SPARX, Speck, and TWINE, on three microcontroller platforms: 8-bit AVR, 16-bit MSP430, and 32-bit ARM. Our results bring some new insights into the question of how well these lightweight ciphers are suited to secure the Internet of things. The benchmarking framework provides cipher designers with an easy-to-use tool to compare new algorithms with the state of the art and allows standardization organizations to conduct a fair and consistent evaluation of a large number of candidates

    A Low-Energy Security Solution for IoT-Based Smart Farms

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    This work proposes a novel configuration of the Transport Layer Security protocol (TLS), suitable for low energy Internet of Things (IoT), applications. The motivation behind the redesign of TLS is energy consumption minimisation and sustainable farming, as exemplified by an application domain of aquaponic smart farms. The work therefore considers decentralisation of a formerly centralised security model, with a focus on reducing energy consumption for battery powered devices. The research presents a four-part investigation into the security solution, composed of a risk assessment, energy analysis of authentication and data exchange functions, and finally the design and verification of a novel consensus authorisation mechanism. The first investigation considered traditional risk-driven threat assessment, but to include energy reduction, working towards device longevity within a content-oriented framework. Since the aquaponics environments include limited but specific data exchanges, a content-oriented approach produced valuable insights into security and privacy requirements that would later be tested by implementing a variety of mechanisms available on the ESP32. The second and third investigations featured the energy analysis of authentication and data exchange functions respectively, where the results of the risk assessment were implemented to compare the re-configurations of TLS mechanisms and domain content. Results concluded that selective confidentiality and persistent secure sessions between paired devices enabled considerable improvements for energy consumptions, and were a good reflection of the possibilities suggested by the risk assessment. The fourth and final investigation proposed a granular authorisation design to increase the safety of access control that would otherwise be binary in TLS. The motivation was for damage mitigation from inside attacks or network faults. The approach involved an automated, hierarchy-based, decentralised network topology to reduce data duplication whilst still providing robustness beyond the vulnerability of central governance. Formal verification using model-checking indicated a safe design model, using four automated back-ends. The research concludes that lower energy IoT solutions for the smart farm application domain are possible

    Design, Cryptanalysis and Protection of Symmetric Encryption Algorithms

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    This thesis covers results from several areas related to symmetric cryptography, secure and efficient implementation and is divided into four main parts: In Part II, Benchmarking of AEAD, two articles will be presented, showing the results of the FELICS framework for Authenticated encryption algorithms, and multiarchitecture benchmarking of permutations used as construction block of AEAD algorithms. The Sparkle family of Hash and AEAD algorithms will be shown in Part III. Sparkle is currently a finalist of the NIST call for standardization of lightweight hash and AEAD algorithms. In Part IV, Cryptanalysis of ARX ciphers, it is discussed two cryptanalysis techniques based on differential trails, applied to ARX ciphers. The first technique, called Meet-in-the-Filter uses an offline trail record, combined with a fixed trail and a reverse differential search to propose long differential trails that are useful for key recovery. The second technique is an extension of ARX analyzing tools, that can automate the generation of truncated trails from existing non-truncated ones, and compute the exact probability of those truncated trails. In Part V, Masked AES for Microcontrollers, is shown a new method to efficiently compute a side-channel protected AES, based on the masking scheme described by Rivain and Prouff. This method introduces table and execution-order optimizations, as well as practical security proofs

    Security protocols for mobile ubiquitous e-health systems

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    Mención Internacional en el título de doctorWearable and implantable medical devices constitute an already established industry nowadays. According to a recent research [113], North America is currently the most important market followed by Europe, Asia-Pacific and the rest of the world. Additionally, the same document remarks the importance of the Asia-Pacific region due to the rising ageing population and the overpopulation in that area. The most common implantable medical devices include pacemakers, defibrillators, cochlear implants, insulin pumps, and neurostimulators among others. In recent years, the proliferation of smartphones and other mobile “smart” devices with substantial computational and communication capabilities have reshaped the way wireless body area network may be implemented. In their current generation (or in a near future), all of them share a common feature: wireless communication capabilities [127]. Moreover, implantable medical devices have the ability to support and store telemetry data facilitating the remote monitoring of the patient. Medical devices can be part of a wireless body area network, operating both as sensors and as actuators and making decisions in real time. On the other hand, a new kind of devices called wearables such as smart bracelets or smart watches have been equipped with several sensors like Photoplethysmogram (PPG) to record the heart beats, accelerometers to count the steps or Global Positioning System (GPS) to geopositioning users and were originally conceived as cheap solutions to help people to improve their workout. However these devices have demonstrated to be quite useful in many healthcare environments due to a huge variety of different and low-cost medical sensors. Thus, patients can be monitored for long periods of time without interfering in their daily life and taking their vital signs constantly under control. Security and privacy issues have been described as two of the most challenging problems of implantable medical devices and, more generally, wireless body area networks [6, 47, 84, 103]. As an example, it has been demonstrated that somebody equipped with a low cost device can eavesdrop on the data exchanged between a reader and a peacemaker and may even induce a cardiac arrest [71]. Health-related data have been the focus of several attacks almost since the adoption of computers in the healthcare domain. As a recent example, in 2010 personal data from more than 26 million of veterans were stolen from the Department of Veterans Affairs’ database in the US by an employee who had access to the database [104]. The Ponemon Institute pointed out that Germany and the US spent in 2013 more than 7.56and7.56 and 11 millions, respectively, to protect personal health records from attacks. This PhD dissertation explores the security and privacy of data in healthcare environments where confidential information is measured in real time by some sensors placed in, on, or around the human body. Security and privacy in medical conditions have been widely studied by the research community, nonetheless with the recent boom of wearable devices, new security issues have arisen. The first part of this dissertation is dedicated to the introduction and to expose both the main motivation and objectives of this PhD Thesis. Additionally the contributions and the organization of this document are also presented. In the second part a recent proposal has been analysed from the security and privacy points of view. From this study, vulnerabilities concerning to full disclosure, impersonation, traceability, de-synchronization, and Denial-of-Service (DoS) attacks have been found. These attacks make the protocol infeasible to be introduced with an adequate security and sufficient privacy protection level. Finally, a new protocol named Fingerprint⁺ protocol for Internet of Thing (IoT) is presented, which is based on ISO/IEC 9798-2 and ISO/IEC 18000-6C and whose security is formally verified using BAN logic. In the third part of this dissertation, a new system based on International Standard Organization (ISO) standards and security National Institute of Standards and Technology (NIST) recommendations have been proposed. First, we present a mutual entity authentication protocol inspired on ISO/IEC 9798 Part 2. This system could be deployed in a hospital where Radio Frequency IDentification (RFID) technology may be used to prune blood-handling errors, i.e., the identities of the patients and blood bags are confirmed (authentication protocol) and after that the matching between both entities is checked (verification step). Second, a secure messaging protocol inspired on ISO/IEC 11770 Part 2 and similar to that used in electronic passports is presented. Nowadays the new generation of medical implants possess wireless connectivity. Imagine a doctor equipped with a reader aims to access the records of vital signals stored on the memory of an implant. In this scenario, the doctor (reader) and the patient (implant) are first mutually authenticated and then a secure exchange of data can be performed. The fourth part of this Thesis provides an architecture based on two cryptographic protocols, the first one is for publishing personal data in a body area network composed of different sensors whereas the second one is designed for sending commands to those sensors by guaranteeing the confidentiality and fine-grained access control to the private data. Both protocols are based on a recently proposed public cryptography paradigm named ciphertext policy attribute-based encryption scheme which is lightweight enough to be embedded into wearable devices and sensors. Contrarily to other proposals made on this field, this architecture allows sensors not only to encrypt data but also to decrypt messages generated by other devices. The fifth part presents a new decentralized attribute based encryption scheme named Decentralized Ciphertext-Policy Attribute Based Searchable Encryption that incorporates ciphertext-policy attribute-based encryption with keyword search over encrypted data. This scheme allows users to (a) encrypt their personal data collected by a Wireless Body Area Network (WBAN) according to a policy of attributes; (b) define a set of keywords to enable other users (e.g., hospital stuff) to perform encrypted search over their personal (encrypted) data; (c) securely store the encrypted data on a semi-honest server and let the semi-honest server run the (encrypted) keyword search. Note that any user can perform a keyword query on the encrypted data, however the decryption of the resulting ciphertexts is possible only for users whose attribute satisfy the policy with which the data had been encrypted. We state and prove the security of our scheme against an honest-but-curious server and a passive adversary. Finally, we implement our system on heterogeneous devices and demonstrate its efficiency and scalability. Finally, this document ends with a conclusions achieved during this PhD and a summary of the main published contributions.Los dispositivos médicos implantables como los marcapasos o las bombas de insulina fueron concebidas originalmente para controlar automáticamente ciertos parámetros biológicos y, llegado el caso, poder actuar ante comportamientos anómalos como ataques cardíacos o episodios de hipoglucemia. Recientemente, han surgido uno dispositivos llamados wearables como las pulseras cuantificadoras, los relojes inteligentes o las bandas pectorales. Estos dispositivos han sido equipados con un número de sensores con capacidad de monitorizar señales vitales como el ritmo cardíaco, los movimientos (acelerómetros) o sistemas de posicionamiento (GPS) entre otros muchas opciones, siendo además una solución asequible y accesible para todo el mundo. A pesar de que el propósito original fue la mejora del rendimiento en actividades deportivas, estos dispositivos han resultado ser de gran utilidad en entornos médicos debido a su amplia variedad de sensores. Esta tecnología puede ayudar al personal médico a realizar seguimientos personalizados, constantes y en tiempo real del comportamiento de los pacientes, sin necesidad de interferir en sus vidas cotidianas. Esta Tesis doctoral está centrada en la seguridad y privacidad en entornos médicos, donde la información es recogida en tiempo real a través de una serie de sensores que pueden estar implantados o equipados en el propio paciente. La seguridad y la privacidad en entornos médicos ha sido el foco de muchos investigadores, no obstante con el reciente auge de los wearables se han generado nuevos retos debido a que son dispositivos con fuertes restricciones de cómputo, de memoria, de tamaño o de autonomía. En la primera parte de este documento, se introduce el problema de la seguridad y la privacidad en el paradigma de Internet de las cosas y haciendo especial hincapié en los entornos médicos. La motivación así como los principales objetivos y contribuciones también forman parte de este primer capítulo introductorio. La segunda parte de esta Tesis presenta un nuevo protocolo de autenticación basado en RFID para IoT. Este capítulo analiza previamente, desde el punto de vista de la seguridad y la privacidad un protocolo publicado recientemente y, tras demostrar que carece de las medidas de seguridad suficientes, un nuevo protocolo llamado Fingerprint⁺ compatible con los estándares de seguridad definidos en el estándar ISO/IEC 9798-2 y EPC-C1G2 (equivalente al estándard ISO/IEC 18000-6C) ha sido propuesto. Un nuevo sistema basado en estándares ISO y en recomendaciones realizadas por el NIST ha sido propuesto en la tercera parte de esta Tesis. En este capítulo se presentan dos protocolos bien diferenciados, el primero de ellos consiste en un protocolo de autenticación basado en el estándar ISO/IEC 9798 Part 2. A modo de ejemplo, este protocolo puede evitar problemas de compatibilidad sanguínea, es decir, primero se confirma que el paciente es quien dice ser y que la bolsa de sangre realmente contiene sangre (proceso de autenticación). Posteriormente se comprueba que esa bolsa de sangre va a ser compatible con el paciente (proceso de verificación). El segundo de los protocolos propuestos consiste en un protocolo seguro para el intercambio de información basado en el estándar ISO/IEC 11770 Part 2 (el mismo que los pasaportes electrónicos). Siguiendo con el ejemplo médico, imaginemos que un doctor equipado con un lector de radiofrecuencia desea acceder a los datos que un dispositivo implantado en el paciente está recopilando. En este escenario tanto el lector como el implante, se deben autenticar mutuamente para poder realizar el intercambio de información de manera segura. En el cuarto capítulo, una nueva arquitectura basada en el modelo de Publish/Subscribe ha sido propuesto. Esta solución está compuesta de dos protocolos, uno para el intercambio de información en una red de área personal y otro para poder reconfigurar el comportamiento de los sensores. Ambos protocolos están diseñados para garantizar tanto la seguridad como la privacidad de todos los datos que se envían en la red. Para ello, el sistema está basado en un sistema de criptografía de clave pública llamado Attribute Based Encryption que es suficientemente ligero y versátil como para ser implementado en dispositivos con altas restricciones de cómputo y de memoria. A continuación, en el quinto capítulo se propone una solución completamente orientada a entornos médicos donde la información que los sensores obtienen de los pacientes es cifrada y almacenada en servidores públicos. Una vez en estos servidores, cualquier usuario con privilegios suficientes puede realizar búsquedas sobre datos cifrados, obtener la información y descifrarla. De manera adicional, antes de que los datos cifrados se manden a la nube, el paciente puede definir una serie de palabras claves que se enlazarán a los datos para permitir posteriormente búsquedas y así obtener la información relacionada a un tema en concreto de manera fácil y eficiente. El último capítulo de esta Tesis se muestran las principales conclusiones obtenidas así como un resumen de las contribuciones científicas publicadas durante el período doctoral.Programa Oficial de Doctorado en Ciencia y Tecnología InformáticaPresidente: Arturo Ribagorda Garnacho.- Secretario: Jorge Blasco Alís.- Vocal: Jesús Garicia López de Lacall

    Electromagnetic Side-Channel Resilience against Lightweight Cryptography

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    Side-channel attacks are an unpredictable risk factor in cryptography. Therefore, observations of leakages through physical parameters, i.e., power and electromagnetic (EM) radiation, etc., of digital devices are essential to minimise vulnerabilities associated with cryptographic functions. Compared to costs in the past, performing side-channel attacks using inexpensive test equipment is becoming a reality. Internet-of-Things (IoT) devices are resource-constrained, and lightweight cryptography is a novel approach in progress towards IoT security. Thus, it would provide sufficient data and privacy protection in such a constrained ecosystem. Therefore, cryptanalysis of physical leakages regarding these emerging ciphers is crucial. EM side-channel attacks seem to cause a significant impact on digital forensics nowadays. Within existing literature, power analysis seems to have considerable attention in research whereas other phenomena, such as EM, should continue to be appropriately evaluated in playing a role in forensic analysis.The emphasis of this thesis is on lightweight cryptanalysis. The preliminary investigations showed no Correlation EManalysis (CEMA) of PRESENT lightweight algorithm. The PRESENT is a block cipher that promises to be adequate for IoT devices, and is expected to be used commercially in the future. In an effort to fill in this research gap, this work examines the capabilities of a correlation EM side-channel attack against the PRESENT. For that, Substitution box (S-box) of the PRESENT was targeted for its 1st round with the use of a minimum number of EM waveforms compared to other work in literature, which was 256. The attack indicates the possibility of retrieving 8 bytes of the secret key out of 10 bytes. The experimental process started from a Simple EMA (SEMA) and gradually enhanced up to a CEMA. The thesis presents the methodology of the attack modelling and the observations followed by a critical analysis. Also, a technical review of the IoT technology and a comprehensive literature review on lightweight cryptology are included
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