7,760 research outputs found
Higher Order Side-Channel Attacks Resilient S-boxes
Masking schemes represent a well-researched and successful option to follow when considering side-channel countermeasures. Still, such measures increase the implementation cost in term of power consumption, clock cycles, and random numbers generation. In fact, the higher the order of protection against side-channel adversaries, the higher the implementation cost of countermeasures.
S-boxes represent the most vulnerable part in an implementation when considering side-channel adversary. In this paper, we investigate how to generate S-boxes that have improved resilience against varying orders of side-channel attacks while minimising the implementation costs. We examine whether S-boxes generated against a certain order of attack also represent a good solution when considering different order of attacks.
We demonstrate that we successfully generated S-boxes resilient against a certain physical attack order but the improvements are small. As a result, S-boxes that are resilient against first order attacks stay resilient against higher-order attacks, which saves computational power during the design of higher-order side-channel attacks resilient S-boxes
DR.SGX: Hardening SGX Enclaves against Cache Attacks with Data Location Randomization
Recent research has demonstrated that Intel's SGX is vulnerable to various
software-based side-channel attacks. In particular, attacks that monitor CPU
caches shared between the victim enclave and untrusted software enable accurate
leakage of secret enclave data. Known defenses assume developer assistance,
require hardware changes, impose high overhead, or prevent only some of the
known attacks. In this paper we propose data location randomization as a novel
defensive approach to address the threat of side-channel attacks. Our main goal
is to break the link between the cache observations by the privileged adversary
and the actual data accesses by the victim. We design and implement a
compiler-based tool called DR.SGX that instruments enclave code such that data
locations are permuted at the granularity of cache lines. We realize the
permutation with the CPU's cryptographic hardware-acceleration units providing
secure randomization. To prevent correlation of repeated memory accesses we
continuously re-randomize all enclave data during execution. Our solution
effectively protects many (but not all) enclaves from cache attacks and
provides a complementary enclave hardening technique that is especially useful
against unpredictable information leakage
A Comprehensive Survey on the Implementations, Attacks, and Countermeasures of the Current NIST Lightweight Cryptography Standard
This survey is the first work on the current standard for lightweight
cryptography, standardized in 2023. Lightweight cryptography plays a vital role
in securing resource-constrained embedded systems such as deeply-embedded
systems (implantable and wearable medical devices, smart fabrics, smart homes,
and the like), radio frequency identification (RFID) tags, sensor networks, and
privacy-constrained usage models. National Institute of Standards and
Technology (NIST) initiated a standardization process for lightweight
cryptography and after a relatively-long multi-year effort, eventually, in Feb.
2023, the competition ended with ASCON as the winner. This lightweight
cryptographic standard will be used in deeply-embedded architectures to provide
security through confidentiality and integrity/authentication (the dual of the
legacy AES-GCM block cipher which is the NIST standard for symmetric key
cryptography). ASCON's lightweight design utilizes a 320-bit permutation which
is bit-sliced into five 64-bit register words, providing 128-bit level
security. This work summarizes the different implementations of ASCON on
field-programmable gate array (FPGA) and ASIC hardware platforms on the basis
of area, power, throughput, energy, and efficiency overheads. The presented
work also reviews various differential and side-channel analysis attacks (SCAs)
performed across variants of ASCON cipher suite in terms of algebraic,
cube/cube-like, forgery, fault injection, and power analysis attacks as well as
the countermeasures for these attacks. We also provide our insights and visions
throughout this survey to provide new future directions in different domains.
This survey is the first one in its kind and a step forward towards
scrutinizing the advantages and future directions of the NIST lightweight
cryptography standard introduced in 2023
Security analysis of NIST-LWC contest finalists
Dissertação de mestrado integrado em Informatics EngineeringTraditional cryptographic standards are designed with a desktop and server environment in mind, so, with the
relatively recent proliferation of small, resource constrained devices in the Internet of Things, sensor networks,
embedded systems, and more, there has been a call for lightweight cryptographic standards with security,
performance and resource requirements tailored for the highly-constrained environments these devices find
themselves in.
In 2015 the National Institute of Standards and Technology began a Standardization Process in order to select
one or more Lightweight Cryptographic algorithms. Out of the original 57 submissions ten finalists remain, with
ASCON and Romulus being among the most scrutinized out of them.
In this dissertation I will introduce some concepts required for easy understanding of the body of work, do
an up-to-date revision on the current situation on the standardization process from a security and performance
standpoint, a description of ASCON and Romulus, and new best known analysis, and a comparison of the two,
with their advantages, drawbacks, and unique traits.Os padrões criptográficos tradicionais foram elaborados com um ambiente de computador e servidor em mente.
Com a proliferação de dispositivos de pequenas dimensões tanto na Internet of Things, redes de sensores e
sistemas embutidos, apareceu uma necessidade para se definir padrões para algoritmos de criptografia leve, com
prioridades de segurança, performance e gasto de recursos equilibrados para os ambientes altamente limitados
em que estes dispositivos operam.
Em 2015 o National Institute of Standards and Technology lançou um processo de estandardização com o
objectivo de escolher um ou mais algoritmos de criptografia leve. Das cinquenta e sete candidaturas originais
sobram apenas dez finalistas, sendo ASCON e Romulus dois desses finalistas mais examinados.
Nesta dissertação irei introduzir alguns conceitos necessários para uma fácil compreensão do corpo deste
trabalho, assim como uma revisão atualizada da situação atual do processo de estandardização de um ponto
de vista tanto de segurança como de performance, uma descrição do ASCON e do Romulus assim como as
suas melhores análises recentes e uma comparação entre os dois, frisando as suas vantagens, desvantagens e
aspectos únicos
Self-triggered Resilient Stabilization of Linear Systems with Quantized Output
This paper studies the problem of stabilizing a self-triggered control system
with quantized output. Employing a standard observer-based state feedback
control law, a self-triggering mechanism that dictates the next sampling time
based on quantized output is co-developed with an output encoding scheme. If,
in addition, the transmission protocols at the controller-to-actuator (C-A) and
sensor-to-controller (S-C) channels can be adapted, the self-triggered control
architecture can be considerably simplified, leveraging a delicate
observer-based deadbeat controller to eliminate the need for running the
controller in parallel at the encoder side. To account for denial-of-service
(DoS) in the S-C channel, the proposed output encoding and self-triggered
control schemes are further made resilient. It is shown that a linear
time-invariant system can be exponentially stabilized if some conditions on the
average DoS duration time are met. There is a trade-off between the maximum
inter-sampling time and the resilience against DoS attacks. Finally, a
numerical example is presented to demonstrate the practical merits of the
proposed self-triggered control schemes and associated theory
MP-CFM: MPTCP-Based communication functional module for next generation ERTMS
184 p.
El contenido de los capítulos 4,5,6,7,8 y 9 está sujeto a confidencialidadEl Sistema Europeo de Gestión del Tráfico Ferroviario (ERTMS, por sus siglasen inglés), fue originalmente diseñado para los ferrocarriles europeos. Sinembargo, a lo largo de las dos últimas décadas, este sistema se ha convertidoen el estándar de-facto para los servicios de Alta Velocidad en la mayoría depaíses desarrollados.El sistema ERTMS se compone de tres subsistemas principales: 1) el Sistemade Control Ferroviario Europeo (ETCS, por sus siglas en inglés), que actúacomo aplicación de señalización; 2) el sistema Euroradio, que a su vez estádividido en dos subsistemas, el Módulo de Seguridad Funcional (SFM, porsus siglas en inglés), y el Módulo de Comunicación Funcional (CFM, porsus siglas en inglés); y 3) el sistema de comunicaciones subyacente, GSM-R,que transporta la información intercambiada entre el sistema embarcado enel tren (OBU, por sus siglas en inglés) y el Centro de Bloqueo por Radio(RBC, por sus siglas en inglés). El sistema de señalización ETCS soporta tresniveles dependiendo del nivel de prestaciones soportadas. En el nivel 3 seintroduce la posibilidad de trabajar con bloques móviles en lugar de bloquesfijos definidos en la vía. Esto implica que la distancia de avance entre dos trenesconsecutivos puede ser reducida a una distancia mínima en la que se garanticela seguridad del servicio, aumentando por tanto la capacidad del corredorferroviario. Esta distancia de seguridad viene determinada por la combinaciónde la distancia de frenado del tren y el retraso de las comunicaciones deseñalización. Por lo tanto, se puede afirmar que existe una relación directaentre los retrasos y la confiabilidad de las transmisiones de las aplicaciones deseñalización y la capacidad operacional de un corredor ferroviario. Así pues,el estudio y mejora de los sistemas de comunicaciones utilizados en ERTMSjuegan un papel clave en la evolución del sistema ERTMS. Asimismo, unaoperatividad segura en ERTMS, desde el punto de vista de las comunicacionesimplicadas en la misma, viene determinada por la confiabilidad de lascomunicaciones, la disponibilidad de sus canales de comunicación, el retrasode las comunicaciones y la seguridad de sus mensajes.Unido este hecho, la industria ferroviaria ha venido trabajando en ladigitalización y la transición al protocolo IP de la mayor parte de los sistemasde señalización. Alineado con esta tendencia, el consorcio industrial UNISIGha publicado recientemente un nuevo modelo de comunicaciones para ERTMSque incluye la posibilidad, no solo de operar con el sistema tradicional,basado en tecnología de conmutación de circuitos, sino también con un nuevosistema basado en IP. Esta tesis está alineada con el contexto de migraciónactual y pretende contribuir a mejorar la disponibilidad, confiabilidad yseguridad de las comunicaciones, tomando como eje fundamental los tiemposde transmisión de los mensajes, con el horizonte puesto en la definición deuna próxima generación de ERTMS, definida en esta tesis como NGERTMS.En este contexto, se han detectado tres retos principales para reforzar laresiliencia de la arquitectura de comunicaciones del NGERTMS: 1) mejorarla supervivencia de las comunicaciones ante disrupciones; 2) superar laslimitaciones actuales de ERTMS para enviar mensajes de alta prioridad sobretecnología de conmutación de paquetes, dotando a estos mensajes de un mayorgrado de resiliencia y menor latencia respecto a los mensajes ordinarios; y3) el aumento de la seguridad de las comunicaciones y el incremento de ladisponibilidad sin que esto conlleve un incremento en la latencia.Considerando los desafíos previamente descritos, en esta tesis se proponeuna arquitectura de comunicaciones basada en el protocolo MPTCP, llamadaMP-CFM, que permite superar dichos desafíos, a la par que mantener laretrocompatibilidad con el sistema de comunicaciones basado en conmutaciónde paquetes recientemente propuesto por UNISIG. Hasta el momento, esta esla primera vez que se propone una arquitectura de comunicaciones completacapaz de abordar los desafíos mencionados anteriormente. Esta arquitecturaimplementa cuatro tipos de clase de servicio, los cuales son utilizados porlos paquetes ordinarios y de alta prioridad para dos escenarios distintos; unescenario en el que ambos extremos, el sistema embarcado o OBU y el RBC,disponen de múltiples interfaces de red; y otro escenario transicional en el cualel RBC sí tiene múltiples interfaces de red pero el OBU solo dispone de unaúnica interfaz. La arquitectura de comunicaciones propuesta para el entornoferroviario ha sido validada mediante un entorno de simulación desarrolladopara tal efecto. Es más, dichas simulaciones demuestran que la arquitecturapropuesta, ante disrupciones de canal, supera con creces en términos derobustez el sistema diseñado por UNISIG. Como conclusión, se puede afirmarque en esta tesis se demuestra que una arquitectura de comunicaciones basadade MPTCP cumple con los exigentes requisitos establecidos para el NGERTMSy por tanto dicha propuesta supone un avance en la evolución del sistema deseñalización ferroviario europeo
Undermining User Privacy on Mobile Devices Using AI
Over the past years, literature has shown that attacks exploiting the
microarchitecture of modern processors pose a serious threat to the privacy of
mobile phone users. This is because applications leave distinct footprints in
the processor, which can be used by malware to infer user activities. In this
work, we show that these inference attacks are considerably more practical when
combined with advanced AI techniques. In particular, we focus on profiling the
activity in the last-level cache (LLC) of ARM processors. We employ a simple
Prime+Probe based monitoring technique to obtain cache traces, which we
classify with Deep Learning methods including Convolutional Neural Networks. We
demonstrate our approach on an off-the-shelf Android phone by launching a
successful attack from an unprivileged, zeropermission App in well under a
minute. The App thereby detects running applications with an accuracy of 98%
and reveals opened websites and streaming videos by monitoring the LLC for at
most 6 seconds. This is possible, since Deep Learning compensates measurement
disturbances stemming from the inherently noisy LLC monitoring and unfavorable
cache characteristics such as random line replacement policies. In summary, our
results show that thanks to advanced AI techniques, inference attacks are
becoming alarmingly easy to implement and execute in practice. This once more
calls for countermeasures that confine microarchitectural leakage and protect
mobile phone applications, especially those valuing the privacy of their users
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