Improved Cryptoanalysis of the Self-shrinking P-adic Cryptographic Generator

The Self-shrinking p-adic cryptographic generator (SSPCG) is a fast software stream cipher. Improved cryptoanalysis of the SSPCG is introduced. This cryptoanalysis makes more precise the length of the period of the generator. The linear complexity and the cryptography resistance against most recently used attacks are invesigated. Then we discuss how such attacks can be avoided. The results show that the sequence generated by a SSPCG has a large period, large linear complexity and is stable against the cryptographic attacks. This gives the reason to consider the SSPSG as suitable for critical cryptographic applications in stream cipher encryption algorithms.

Long-range, high bit-rate secure key distribution link utilizing Raman Ultra-long fiber laser (UFL)

The distribution of the secret key is the weakest link of many data encryption systems. Quantum key distribution (QKD) schemes provide attractive solutions [1], however their implementation remains challenging and their range and bit-rate are limited. Moreover, practical QKD systems, employ real-life components and are, therefore, vulnerable to diverse attack schemes [2]. Ultra-Long fiber lasers (UFLs) have been drawing much attention recently because of their fundamentally different properties compared to conventional lasers as well as their unique applications [3]. Here, we demonstrate a 100Bps, practically secure key distribution, over a 500km link, employing Raman gain UFL. Fig. 1(a) depicts a schematic of the UFL system. Each user has an identical set of two wavelength selective mirrors centered at l0 and l 1. In order to exchange a key-bit, each user independently choose one of these mirrors and introduces it as a laser reflector at their end. If both users choose identical mirrors, a clear signal develops and the bits in these cases are discarded. However if they choose complementary mirrors, (1, 0 or 0, 1 states), the UFL remains below lasing threshold and no signal evolves. In these cases, an eavesdropper can only detect noise and is unable to determine the mirror choice of the users, where the choice of mirrors represent a single key bit (e.g. Alice's choice of mirror is the key-bit). These bits are kept and added to the key. The absence of signal in the secure states faxilitates fast measurements to distinguish between the non-secure and the secure states and to determine the key-bit in the later case, Sequentially reapeating the single bit exchange protocol generate the entire keys of any desirable length. © 2013 IEEE.

Plaintext Recovery in DES-like Cryptosystems Based on S-boxes with Embedded Parity Check

We describe an approach for recovering the plaintext in block ciphers having a design structure similar to the Data Encryption Standard but with improperly constructed S-boxes. The experiments with a backtracking search algorithm performing this kind of attack against modified DES/Triple-DES in ECB mode show that the unknown plaintext can be recovered with a small amount of uncertainty and this algorithm is highly efficient both in time and memory costs for plaintext sources with relatively low entropy. Our investigations demonstrate once again that modifications resulting to S-boxes which still satisfy some design criteria may lead to very weak ciphers. ACM Computing Classification System (1998): E.3, I.2.7, I.2.8.

Metropolitan Tourism Experience Development. Selected studies from the Tourism Network Workshop of the Regional Studies Association, held in Budapest, Hungary, 2015

On January 28-30, 2015 Corvinus University of Budapest hosted the latest workshop of the Regional Studies Association’s Tourism Research Network. The event had been held previously in Izmir, Aalborg, Warsaw, Östersund, Antalya, Leeds and Vila-seca Catalonia. The aim of the RSA research network is to examine tourism diversity from the perspective of regional development in order to identify current challenges and opportunities in a systematic manner, and hence provide the basis for a more well-informed integration of tourism in regional development strategies and move beyond political short-termism and buzzword fascination. In the frame of the network a series of workshops have been organised from various topics of destination management till rural tourism.

Az innováció társadalmi felelőssége

A szerző kutatásának legfőbb eredménye egy új fogalom megalkotása: az innováció társadalmi felelőssége. Az innováció a gazdasági élet fontos és nélkülözhetetlen eleme. Ez az általános megközelítés jellemzi az innovációs folyamatok kutatását is. Nem vitatva az innovációk hasznosságának igazságát, ebben az írásban kiszélesíti ezt az általánosan használt és szigorúan korlátozott megközelítést. Tapasztalatai és kutatásainak eredményei szerint két új megközelítéssel gazdagítja az innováció fogalmát. Az első az innovációk feltétlen hasznosságával kapcsolatos. Az innovációk veszélyesek is lehetnek. Megemlítve az atombombát, a DDT rovarirtót vagy a szintetikus kábítószereket, világos lehet, hogy mit tart veszélyes innovációnak. Az innováció fogalmának értelmezésében egy további új területre utal. Nemcsak a gazdaságban, de a társadalmi élet egészében ismertek az innovációk. A szocializmus, ez a jelentős és végső soron sikertelen társadalmi innováció a legjelentősebb példa a sikertelen társadalmi innovációra. Napjainkban is találkozni lehet kétes hozadékú társadalmi innovációkkal. Írása néhány példát említ a mai veszélyes kimenetelű intellektuális kezdeményezésekből is.

Esti mesék a kockázatról

Amikor ezt a dolgozatot elkezdtem, még arra gondoltam, hogy csak az operációkutatás közismert modellje, a raktárkészletezés matematikai elmélete és a likviditáskezelés közötti párhuzamról fogok írni. A dolgozat írása közben törtek ki a Buda-Cash és a Quaestor körüli, azt kell mondanom, ügyeletes botrányok. Ugyancsak ebben az időszakban kapott újabb lendületet a devizahitelezéssel kapcsolatos vita: ki mikor mit hibázott, illetve volt-e bárki, aki ne hibázott volna? A Buda-Cash- és a Quaestor-ügyben felmerülő, legmeglepőbb fordulat az állítólagos több százmilliárd forint veszteségen túl az volt, hogy mindezt tizenöt év áldozatos munkájával sikerült összehozni. Még ha ezek az információk első felindulásból született megjegyzések, akkor is magyarázatra szorulnak. Így vagy úgy. Ha igaz, akkor hogyan képzelhető ez el, ha nem igaz, akkor miből ered az a látszat, hogy ez így történt? A felmerülő kérdések és az ellentmondások nyilvánvalóak. A legfőbb kérdés azonban a következő: mit is csinálnak a kockázatkezelők? Miért is fizetjük őket? Mennyire bízhatunk bennük?

Secure information flow via stripping and fast simulation

Type systems for secure information flow aim to prevent a program from leaking information from H (high) to L (low) variables. Traditionally, bisimulation has been the prevalent technique for proving the soundness of such systems. This work introduces a new proof technique based on stripping and fast simulation, and shows that it can be applied in a number of cases where bisimulation fails. We present a progressive development of this technique over a representative sample of languages including a simple imperative language (core theory), a multiprocessing nondeterministic language, a probabilistic language, and a language with cryptographic primitives. In the core theory we illustrate the key concepts of this technique in a basic setting. A fast low simulation in the context of transition systems is a binary relation where simulating states can match the moves of simulated states while maintaining the equivalence of low variables; stripping is a function that removes high commands from programs. We show that we can prove secure information flow by arguing that the stripping relation is a fast low simulation. We then extend the core theory to an abstract distributed language under a nondeterministic scheduler. Next, we extend to a probabilistic language with a random assignment command; we generalize fast simulation to the setting of discrete time Markov Chains, and prove approximate probabilistic noninterference. Finally, we introduce cryptographic primitives into the probabilistic language and prove computational noninterference, provided that the underling encryption scheme is secure.

Two-bit pattern analysis for quantitative information flow

Protecting confidential information from improper disclosure is a fundamental security goal. While encryption and access control are important tools for ensuring confidentiality, they cannot prevent an authorized system from leaking confidential information to its publicly observable outputs, whether inadvertently or maliciously. Hence, secure information flow aims to provide end-to-end control of information flow. Unfortunately, the traditionally-adopted policy of noninterference, which forbids all improper leakage, is often too restrictive. Theories of quantitative information flow address this issue by quantifying the amount of confidential information leaked by a system, with the goal of showing that it is intuitively "small" enough to be tolerated. Given such a theory, it is crucial to develop automated techniques for calculating the leakage in a system. ^ This dissertation is concerned with program analysis for calculating the maximum leakage, or capacity, of confidential information in the context of deterministic systems and under three proposed entropy measures of information leakage: Shannon entropy leakage, min-entropy leakage, and g-leakage. In this context, it turns out that calculating the maximum leakage of a program reduces to counting the number of possible outputs that it can produce. ^ The new approach introduced in this dissertation is to determine two-bit patterns, the relationships among pairs of bits in the output; for instance we might determine that two bits must be unequal. By counting the number of solutions to the two-bit patterns, we obtain an upper bound on the number of possible outputs. Hence, the maximum leakage can be bounded. We first describe a straightforward computation of the two-bit patterns using an automated prover. We then show a more efficient implementation that uses an implication graph to represent the two- bit patterns. It efficiently constructs the graph through the use of an automated prover, random executions, STP counterexamples, and deductive closure. The effectiveness of our techniques, both in terms of efficiency and accuracy, is shown through a number of case studies found in recent literature. ^

The 128-bit block cipher MARS

The purpose of the research is to investigate the emerging data security methodologies that will work with most suitable applications in the academic, industrial and commercial environments. Of several methodologies considered for Advanced Encryption Standard (AES), MARS (block cipher) developed by IBM, has been selected. Its design takes advantage of the powerful capabilities of modern computers to allow a much higher level of performance than can be obtained from less optimized algorithms such as Data Encryption Standards (DES). MARS is unique in combining virtually every design technique known to cryptographers in one algorithm. The thesis presents the performance of 128-bit cipher flexibility, which is a scaled down version of the algorithm MARS. The cryptosystem used showed equally comparable performance in speed, flexibility and security, with that of the original algorithm. The algorithm is considered to be very secure and robust and is expected to be implemented for most of the applications.

Algoritmo papílio como método de proteção de templates para aumentar a segurança em sistemas de identificação biométricos

There are authentication models which use passwords, keys, personal identifiers (cards, tags etc) to authenticate a particular user in the authentication/identification process. However, there are other systems that can use biometric data, such as signature, fingerprint, voice, etc., to authenticate an individual in a system. In another hand, the storage of biometric can bring some risks such as consistency and protection problems for these data. According to this problem, it is necessary to protect these biometric databases to ensure the integrity and reliability of the system. In this case, there are models for security/authentication biometric identification, for example, models and Fuzzy Vault and Fuzzy Commitment systems. Currently, these models are mostly used in the cases for protection of biometric data, but they have fragile elements in the protection process. Therefore, increasing the level of security of these methods through changes in the structure, or even by inserting new layers of protection is one of the goals of this thesis. In other words, this work proposes the simultaneous use of encryption (Encryption Algorithm Papilio) with protection models templates (Fuzzy Vault and Fuzzy Commitment) in identification systems based on biometric. The objective of this work is to improve two aspects in Biometric systems: safety and accuracy. Furthermore, it is necessary to maintain a reasonable level of efficiency of this data through the use of more elaborate classification structures, known as committees. Therefore, we intend to propose a model of a safer biometric identification systems for identification.

A PHR system with policy-based fine-grained access control and revocation mechanism

Collaborative sharing of information is becoming much more needed technique to achieve complex goals in today's fast-paced tech-dominant world. Personal Health Record (PHR) system has become a popular research area for sharing patients informa- tion very quickly among health professionals. PHR systems store and process sensitive information, which should have proper security mechanisms to protect patients' private data. Thus, access control mechanisms of the PHR should be well-defined. Secondly, PHRs should be stored in encrypted form. Cryptographic schemes offering a more suitable solution for enforcing access policies based on user attributes are needed for this purpose. Attribute-based encryption can resolve these problems, we propose a patient-centric framework that protects PHRs against untrusted service providers and malicious users. In this framework, we have used Ciphertext Policy Attribute Based Encryption scheme as an efficient cryptographic technique, enhancing security and privacy of the system, as well as enabling access revocation. Patients can encrypt their PHRs and store them on untrusted storage servers. They also maintain full control over access to their PHR data by assigning attribute-based access control to selected data users, and revoking unauthorized users instantly. In order to evaluate our system, we implemented CP-ABE library and web services as part of our framework. We also developed an android application based on the framework that allows users to register into the system, encrypt their PHR data and upload to the server, and at the same time authorized users can download PHR data and decrypt it. Finally, we present experimental results and performance analysis. It shows that the deployment of the proposed system would be practical and can be applied into practice.

Performance scolaire et régulation par les connaissances en éducation

Depuis une vingtaine d’années, les systèmes d’enseignement de très nombreux pays sont engagés dans des transformations profondes de leurs politiques éducatives. D’une part, on assiste progressivement à une globalisation et à une européanisation des politiques éducatives. Si elles restent formellement définies par les États, ces dernières sont de plus en plus enchâssées dans des procédures de mise en comparaison de leurs résultats (via par exemple les classements des pays produits par l’enquête Pisa de l’OCDE ; Lingard/Rawolle/Taylor, 2005 ; Mangez/Cattonar, 2009) et dans des procédures de coordination de leurs objectifs. Ainsi en Europe, les ministres de l’éducation des États-membres, avec l’aide de la Commission européenne, se sont mis d’accord sur un “Cadre européen Éducation et formation tout au long de la vie” (CEEFTLV)1. Les objectifs sont formulés en s’appuyant sur la définition d’indicateurs et de niveaux de référence de ces indicateurs (benchmark) que chaque pays s’engage à essayer d’atteindre. Les objectifs opérationnels sont formulés sous forme de “chiffres” de référence. Comme l’avance Ozga (2009), on gouverne par les “nombres”. Cette construction progressive d’un “espace européen de l’éducation” s’opère notamment par la mise en place de dispositifs de “coordination” basés sur ces outils (Lawn/Grek, 2012).

Processus de traduction et institutionnalisation d’outils de régulation basés sur les connaissances dans l’enseignement primaire en Belgique

Depuis une quinzaine d’années, on assiste en Belgique francophone au développement d’une politique d’évaluation externe des écoles. Notre étude analyse la réception de cette politique par les acteurs locaux (directeurs et enseignants d’écoles primaires) et intermédiaires (inspecteurs) et montre comment les outils de régulation basés sur les connaissances mis en place par ces acteurs affectent la réception et la légitimité de la politique d’évaluation dans son ensemble. À l’aide de la sociologie de la traduction (Callon & Latour) et de la théorie néoinstitutionnaliste, nous comparons deux modes de construction et de mise en oeuvre de cette politique dans deux zones d’inspection. Dans la première, le dispositif repose pour l’essentiel sur la bureaucratie, tandis que dans la seconde la politique est construite par un réseau d’acteurs locaux et intermédiaires. Nous montrons que 1) les rôles et les stratégies des acteurs intermédiaires diffèrent considérablement ; 2) les différences constatées dans la construction de la politique d’évaluation (co-construction des outils par un réseau d’acteurs intermédiaires d’un côté, mise en oeuvre hiérarchique et bureaucratique de l’autre) sont liées aux différents effets des outils de régulation sur les pratiques des enseignants et sur la légitimité de cette politique.

PoisonIvy: Safe speculation for secure memory

Encryption and integrity trees guard against phys- ical attacks, but harm performance. Prior academic work has speculated around the latency of integrity verification, but has done so in an insecure manner. No industrial implementations of secure processors have included speculation. This work presents PoisonIvy, a mechanism which speculatively uses data before its integrity has been verified while preserving security and closing address-based side-channels. PoisonIvy reduces per- formance overheads from 40% to 20% for memory intensive workloads and down to 1.8%, on average.

Performance scolaire et régulation par les connaissances en éducation

Depuis une vingtaine d’années, les systèmes d’enseignement de très nombreux pays sont engagés dans des transformations profondes de leurs politiques éducatives. D’une part, on assiste progressivement à une globalisation et à une européanisation des politiques éducatives. Si elles restent formellement définies par les États, ces dernières sont de plus en plus enchâssées dans des procédures de mise en comparaison de leurs résultats (via par exemple les classements des pays produits par l’enquête Pisa de l’OCDE ; Lingard/Rawolle/Taylor, 2005 ; Mangez/Cattonar, 2009) et dans des procédures de coordination de leurs objectifs. Ainsi en Europe, les ministres de l’éducation des États-membres, avec l’aide de la Commission européenne, se sont mis d’accord sur un “Cadre européen Éducation et formation tout au long de la vie” (CEEFTLV)1. Les objectifs sont formulés en s’appuyant sur la définition d’indicateurs et de niveaux de référence de ces indicateurs (benchmark) que chaque pays s’engage à essayer d’atteindre. Les objectifs opérationnels sont formulés sous forme de “chiffres” de référence. Comme l’avance Ozga (2009), on gouverne par les “nombres”. Cette construction progressive d’un “espace européen de l’éducation” s’opère notamment par la mise en place de dispositifs de “coordination” basés sur ces outils (Lawn/Grek, 2012).