Space-efficient, byte-wise incremental and perfectly private encryption schemes

The problem raised by incremental encryption is the overhead due to the larger storage space required by the provision of random blocks together with the ciphered versions of a given document. Besides, permitting variable-length modifications on the ciphertext leads to privacy preservation issues. In this paper we present incremental encryption schemes which are space-efficient, byte-wise incremental and which preserve perfect privacy in the sense that they hide the fact that an update operation has been performed on a ciphered document. For each scheme, the run time of updates performed turns out to be very efficient and we discuss the statistically adjustable trade-off between computational cost and storage space required by the produced ciphertexts

EFFICIENT HARDWARE PRIMITIVES FOR SECURING LIGHTWEIGHT SYSTEMS

In the era of IoT and ubiquitous computing, the collection and communication of sensitive data is increasingly being handled by lightweight Integrated Circuits. Efficient hardware implementations of crytographic primitives for resource constrained applications have become critical, especially block ciphers which perform fundamental operations such as encryption, decryption, and even hashing. We study the efficiency of block ciphers under different implementation styles. For low latency applications that use unrolled block cipher implementations, we design a glitch filter to reduce energy consumption. For lightweight applications, we design a novel architecture for the widely used AES cipher. The design eliminates inefficiencies in data movement and clock activity, thereby significantly improving energy efficiency over state-of-the-art architectures. Apart from efficiency, vulnerability to implementation attacks are a concern, which we mitigate by our randomization capable lightweight AES architecture. We fabricate our designs in a commercial 16nm FinFET technology and present measured testchip data on energy consumption and side channel resistance. Finally, we address the problem of supply chain security by using image processing techniques to extract fingerprints from surface texture of plastic IC packages for IC authentication and counterfeit prevention. Collectively these works present efficient and cost effective solutions to secure lightweight systems

YPIR: High-Throughput Single-Server PIR with Silent Preprocessing

We introduce YPIR, a single-server private information retrieval (PIR) protocol that achieves high throughput (up to 75% of the memory bandwidth of the machine) without any offline communication. For retrieving a 1-bit (or 1-byte) record from a 32-GB database, YPIR achieves 10.9 GB/s/core server throughput and requires 2.5 MB of total communication. On the same setup, the state-of-the-art SimplePIR protocol achieves a 12.6 GB/s/core server throughput, requires 1.5 MB total communication, but additionally requires downloading a 724 MB hint in an offline phase. YPIR leverages a new lightweight technique to remove the hint from high-throughput single-server PIR schemes with small overhead. We also show how to reduce the server preprocessing time in the SimplePIR family of protocols by a factor of $10$-$15\times$. By removing the need for offline communication, YPIR significantly reduces the server-side costs for private auditing of Certificate Transparency logs. Compared to the best previous PIR-based approach, YPIR reduces the server-side costs by a factor of $5.6\times$. Note that to reduce communication costs, the previous approach assumed that updates to the Certificate Transparency log servers occurred in weekly batches. Since there is no offline communication in YPIR, our approach allows clients to always audit the most recent Certificate Transparency logs (e.g., updating once a day). Supporting daily updates using the prior scheme would cost $30\times$ more than YPIR (based on current AWS compute costs)

Analysis and Improvement of an Authentication Scheme in Incremental Cryptography

International audienceIntroduced in cryptography by Bellare, Goldreich and Goldwasser in 1994, incrementality is an attractive feature that enables to update efficiently a cryptographic output like a ciphertext, a signature or an authentication tag after modifying the corresponding input. This property is very valuable in large scale systems where gigabytes of data are continuously processed (e.g. in cloud storage). Adding cryptographic operations on such systems can decrease dramatically their performance and incrementality is an interesting solution to have security at a reduced cost.We focus on the so-called XOR-scheme, the first incremental authentication construction proposed by Bellare, Goldreich and Goldwasser, and the only strongly incremental scheme (i.e. incremental regarding insert and delete update operations at any position in a document). Surprisingly, we found a simple attack on this construction that breaks the basic security claimed by the authors in 1994 with only one authentication query (not necessarily chosen). Our analysis gives different ways to fix the scheme; some of these patches are discussed in this paper and we provide a security proof for one of them

Criptografía ligera en dispositivos de identificación por radiofrecuencia- RFID

Esta tesis se centra en el estudio de la tecnología de identificación por radiofrecuencia (RFID), la cual puede ser considerada como una de las tecnologías más prometedoras dentro del área de la computación ubicua. La tecnología RFID podría ser el sustituto de los códigos de barras. Aunque la tecnología RFID ofrece numerosas ventajas frente a otros sistemas de identificación, su uso lleva asociados riesgos de seguridad, los cuales no son fáciles de resolver. Los sistemas RFID pueden ser clasificados, atendiendo al coste de las etiquetas, distinguiendo principalmente entre etiquetas de alto coste y de bajo coste. Nuestra investigación se centra fundamentalmente en estas últimas. El estudio y análisis del estado del arte nos ha permitido identificar la necesidad de desarrollar soluciones criptográficas ligeras adecuadas para estos dispositivos limitados. El uso de soluciones criptográficas estándar supone una aproximación correcta desde un punto de vista puramente teórico. Sin embargo, primitivas criptográficas estándar (funciones resumen, código de autenticación de mensajes, cifradores de bloque/flujo, etc.) exceden las capacidades de las etiquetas de bajo coste. Por tanto, es necesario el uso de criptografía ligera._______________________________________This thesis examines the security issues of Radio Frequency Identification (RFID) technology, one of the most promising technologies in the field of ubiquitous computing. Indeed, RFID technology may well replace barcode technology. Although it offers many advantages over other identification systems, there are also associated security risks that are not easy to address. RFID systems can be classified according to tag price, with distinction between high-cost and low-cost tags. Our research work focuses mainly on low-cost RFID tags. An initial study and analysis of the state of the art identifies the need for lightweight cryptographic solutions suitable for these very constrained devices. From a purely theoretical point of view, standard cryptographic solutions may be a correct approach. However, standard cryptographic primitives (hash functions, message authentication codes, block/stream ciphers, etc.) are quite demanding in terms of circuit size, power consumption and memory size, so they make costly solutions for low-cost RFID tags. Lightweight cryptography is therefore a pressing need. First, we analyze the security of the EPC Class-1 Generation-2 standard, which is considered the universal standard for low-cost RFID tags. Secondly, we cryptanalyze two new proposals, showing their unsuccessful attempt to increase the security level of the specification without much further hardware demands. Thirdly, we propose a new protocol resistant to passive attacks and conforming to low-cost RFID tag requirements. In this protocol, costly computations are only performed by the reader, and security related computations in the tag are restricted to very simple operations. The protocol is inspired in the family of Ultralightweight Mutual Authentication Protocols (UMAP: M2AP, EMAP, LMAP) and the recently proposed SASI protocol. The thesis also includes the first published cryptanalysis of xi SASI under the weakest attacker model, that is, a passive attacker. Fourthly, we propose a new protocol resistant to both passive and active attacks and suitable for moderate-cost RFID tags. We adapt Shieh et.’s protocol for smart cards, taking into account the unique features of RFID systems. Finally, because this protocol is based on the use of cryptographic primitives and standard cryptographic primitives are not supported, we address the design of lightweight cryptographic primitives. Specifically, we propose a lightweight hash function (Tav-128) and a lightweight Pseudo-Random Number Generator (LAMED and LAMED-EPC).We analyze their security level and performance, as well as their hardware requirements and show that both could be realistically implemented, even in low-cost RFID tags

Development of a Security-Focused Multi-Channel Communication Protocol and Associated Quality of Secure Service (QoSS) Metrics

The threat of eavesdropping, and the challenge of recognizing and correcting for corrupted or suppressed information in communication systems is a consistent challenge. Effectively managing protection mechanisms requires an ability to accurately gauge the likelihood or severity of a threat, and adapt the security features available in a system to mitigate the threat. This research focuses on the design and development of a security-focused communication protocol at the session-layer based on a re-prioritized communication architecture model and associated metrics. From a probabilistic model that considers data leakage and data corruption as surrogates for breaches of confidentiality and integrity, a set of metrics allows the direct and repeatable quantification of the security available in single- or multi-channel networks. The quantification of security is based directly upon the probabilities that adversarial listeners and malicious disruptors are able to gain access to or change the original message. Fragmenting data across multiple channels demonstrates potential improvements to confidentiality, while duplication improves the integrity of the data against disruptions. Finally, the model and metrics are exercised in simulation. The ultimate goal is to minimize the information available to adversaries

Integrity and access control in untrusted content distribution networks

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2005.Vita.Includes bibliographical references (p. 129-142).A content distribution network (CDN) makes a publisher's content highly available to readers through replication on remote computers. Content stored on untrusted servers is susceptible to attack, but a reader should have confidence that content originated from the publisher and that the content is unmodified. This thesis presents the SFS read-only file system (SFSRO) and key regression in the Chefs file system for secure, efficient content distribution using untrusted servers for public and private content respectively. SFSRO ensures integrity, authenticity, and freshness of single-writer, many-reader content. A publisher creates a digitally-signed database representing the contents of a source file system. Untrusted servers replicate the database for high availability. Chefs extends SFSRO with key regression to support decentralized access control of private content protected by encryption. Key regression allows a client to derive past versions of a key, reducing the number of keys a client must fetch from the publisher. Thus, key regression reduces the bandwidth requirements of publisher to make keys available to many clients.(cont.) Contributions of this thesis include the design and implementation of SFSRO and Chefs; a concrete definition of security, provably-secure constructions, and an implementation of key regression; and a performance evaluation of SFSRO and Chefs confirming that latency for individual clients remains low, and a single server can support many simultaneous clients.by Kevin E. Fu.Ph.D

Enhancing Automated Network Management

Network management benefits from automated tools. With the recent advent of software-defined principles, automated tools have been proposed from both industry and academia to fulfill function components in the network management control loop. While automation aims to accommodate the ever increasing network diversity and dynamics with improved reliability and management efficiency, it also brings new concerns as it’s becoming more difficult to understand the control of the network and operators cannot rely on traditional troubleshooting tools. Meanwhile, how to effectively integrate new automation tools with existing legacy networks remains a question. This dissertationpresents efficient methods to address key functionalities within the control loop in the adaption of automated network management.Identifying the network-wide forwarding behaviors of a packet is essential for many network management tasks, including policy enforcement, rule verification, and fault localization. We start by presenting AP Classifier. AP Classifier was developed based on the concept of atomic predicates which can be used to characterize the forwarding behaviors of packets. There is an increasing trend that enterprises outsource their Network Function (NF) processing to a cloud to lower cost and ease management. To avoid threats to the enterprise’s private information, we propose SICS based on AP Classifier, a secure and dynamic NF outsourcing framework. Stateful NFs have become essential parts of modern networks, increasing the complexity in network management. A major step in network automation is to automatically translate high level network intents into low level configurations. To ensure those configurations and the states generated by automation match intents, we present Epinoia, a network intent checker for stateful networks. While the concept of auto-translation sounds promising, operators may not know what intents should be. To close the control loop, we present AutoInfer to automatically infer intents of running networks, which helps operators understand the network runtime states

Exploitation of Unintentional Information Leakage from Integrated Circuits

Unintentional electromagnetic emissions are used to recognize or verify the identity of a unique integrated circuit (IC) based on fabrication process-induced variations in a manner analogous to biometric human identification. The effectiveness of the technique is demonstrated through an extensive empirical study, with results presented indicating correct device identification success rates of greater than 99:5%, and average verification equal error rates (EERs) of less than 0:05% for 40 near-identical devices. The proposed approach is suitable for security applications involving commodity commercial ICs, with substantial cost and scalability advantages over existing approaches. A systematic leakage mapping methodology is also proposed to comprehensively assess the information leakage of arbitrary block cipher implementations, and to quantitatively bound an arbitrary implementation\u27s resistance to the general class of differential side channel analysis techniques. The framework is demonstrated using the well-known Hamming Weight and Hamming Distance leakage models, and approach\u27s effectiveness is demonstrated through the empirical assessment of two typical unprotected implementations of the Advanced Encryption Standard. The assessment results are empirically validated against correlation-based differential power and electromagnetic analysis attacks