Easing the Transition from Inspiration to Implementation: A Rapid Prototyping Platform for Wireless Medium Access Control Protocols

Packet broadcast networks are in widespread use in modern wireless communication systems. Medium access control is a key functionality within such technologies. A substantial research effort has been and continues to be invested into the study of existing protocols and the development of new and specialised ones. Academic researchers are restricted in their studies by an absence of suitable wireless MAC protocol development methods. This thesis describes an environment which allows rapid prototyping and evaluation of wireless medium access control protocols. The proposed design flow allows specification of the protocol using the specification and description language (SDL) formal description technique. A tool is presented to convert the SDL protocol description into a C++ model suitable for integration into both simulation and implementation environments. Simulations at various levels of abstraction are shown to be relevant at different stages of protocol design. Environments based on the Cinderella SDL simulator and the ns-2 network simulator have been developed which allow early functional verification, along with detailed and accurate performance analysis of protocols under development. A hardware platform is presented which allows implementation of protocols with flexibility in the hardware/software trade-off. Measurement facilities are integral to the hardware framework, and provide a means for accurate real-world feedback on protocol performance

What use are formal design and analysis methods to telecommunications services?

Have formal methods failed, or will they fail, to help us solve problems of detecting and resolving of feature interactions in telecommunications software? This paper contains SWOT(Strengths, Weaknesses, Opportunities and Threats) analysis of the use of formula design and analysis methods in feature interaction analysis and makes some suggestions for future research

Performance modelling for system-level design

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Data Transfers Analysis in Computer Assisted Design Flow of FPGA Accelerators for Aerospace Systems

The integration of Field Programmable Gate Arrays (FPGAs) in an aerospace system improves its efficiency and its flexibility thanks to their programmability, but increases the design complexity. The design flows indeed have to be composed of several steps to fill the gap between the starting solution, which is usually a reference sequential implementation, and the final heterogeneous solution which includes custom hardware accelerators. Among these steps, there are the analysis of the application to identify the functionalities that gain advantages in execution on hardware and the generation of their implementations by means of Hardware Description Languages. Generating these descriptions for a software developer can be a very difficult task because of the different programming paradigms of software programs and hardware descriptions. To facilitate the developer in this activity, High Level Synthesis techniques have been developed aiming at (semi-)automatically generating hardware implementations of specifications written in high level languages (e.g., C). With respect to other embedded systems scenarios, the aerospace systems introduce further constraints that have to be taken into account during the design of these heterogeneous systems. In this type of systems explicit data transfers to and from FPGAs are preferred to the adoption of a shared memory architecture. The first approach indeed potentially improves the predictability of the produced solutions, but the sizes of all the data transferred to and from any devices must be known at design time. Identifying the sizes in presence of complex C applications which use pointers can be a not so easy task. In this paper, a semi-automatic design flow based on the integration of an aerospace design flow, an application analysis technique, and High Level Synthesis methodologies is presented. The initial reference application is analyzed to identify which are the sizes of the data exchanged among the different components of the application. Next, starting from the high level specification and from the results of this analysis, High Level Synthesis techniques are applied to automatically produce the hardware accelerators

Development of Secure Software : Rationale, Standards and Practices

The society is run by software. Electronic processing of personal and financial data forms the core of nearly all societal and economic activities, and concerns every aspect of life. Software systems are used to store, transfer and process this vital data. The systems are further interfaced by other systems, forming complex networks of data stores and processing entities.This data requires protection from misuse, whether accidental or intentional. Elaborate and extensive security mechanisms are built around the protected information assets. These mechanisms cover every aspect of security, from physical surroundings and people to data classification schemes, access control, identity management, and various forms of encryption. Despite the extensive information security effort, repeated security incidents keep compromising our financial assets, intellectual property, and privacy. In addition to the direct and indirect cost, they erode the trust in the very foundation of information security: availability, integrity, and confidentiality of our data. Lawmakers at various national and international levels have reacted by creating a growing body of regulation to establish a baseline for information security. Increased awareness of information security issues has led to extend this regulation to one of the core issues in secure data processing: security of the software itself. Information security contains many aspects. It is generally classified into organizational security, infrastructure security, and application security. Within application security, the various security engineering processes and techniques utilized at development time form the discipline of software security engineering. The aim of these security activities is to address the software-induced risk toward the organization, reduce the security incidents and thereby lower the lifetime cost of the software. Software security engineering manages the software risk by implementing various security controls right into the software, and by providing security assurance for the existence of these controls by verification and validation. A software development process has typically several objectives, of which security may form only a part. When security is not expressly prioritized, the development organizations have a tendency to direct their resources to the primary requirements. While producing short-term cost and time savings, the increased software risk, induced by a lack of security and assurance engineering, will have to be mitigated by other means. In addition to increasing the lifetime cost of software, unmitigated or even unidentified risk has an increased chance of being exploited and cause other software issues. This dissertation concerns security engineering in agile software development. The aim of the research is to find ways to produce secure software through the introduction of security engineering into the agile software development processes. Security engineering processes are derived from extant literature, industry practices, and several national and international standards. The standardized requirements for software security are traced to their origins in the late 1960s, and the alignment of the software engineering and security engineering objectives followed from their original challenges to the current agile software development methods. The research provides direct solutions to the formation of security objectives in software development, and to the methods used to achieve them. It also identifies and addresses several issues and challenges found in the integration of these activities into the development processes, providing directly applicable and clearly stated solutions for practical security engineering problems. The research found the practices and principles promoted by agile and lean software development methods to be compatible with many security engineering activities. Automated, tool-based processes and the drive for efficiency and improved software quality were found to directly support the security engineering techniques and objectives. Several new ways to integrate software engineering into agile software development processes were identified. Ways to integrate security assurance into the development process were also found, in the form of security documentation, analyses, and reviews. Assurance artifacts can be used to improve software design and enhance quality assurance. In contrast, detached security engineering processes may create security assurance that serves only purposes external to the software processes. The results provide direct benefits to all software stakeholders, from the developers and customers to the end users. Security awareness is the key to more secure software. Awareness creates a demand for security, and the demand gives software developers the concrete objectives and the rationale for the security work. This also creates a demand for new security tools, processes and controls to improve the efficiency and effectiveness of software security engineering. At first, this demand is created by increased security regulation. The main pressure for change will emanate from the people and organizations utilizing the software: security is a mandatory requirement, and software must provide it. This dissertation addresses these new challenges. Software security continues to gain importance, prompting for new solutions and research.Ohjelmistot ovat keskeinen osa yhteiskuntamme perusinfrastruktuuria. Merkittävä osa sosiaalisesta ja taloudellisesta toiminnastamme perustuu tiedon sähköiseen käsittelyyn, varastointiin ja siirtoon. Näitä tehtäviä suorittamaan on kehitetty merkittävä joukko ohjelmistoja, jotka muodostavat mutkikkaita tiedon yhteiskäytön mahdollistavia verkostoja. Tiedon suojaamiseksi sen ympärille on kehitetty lukuisia suojamekanismeja, joiden tarkoituksena on estää tiedon väärinkäyttö, oli se sitten tahatonta tai tahallista. Suojausmekanismit koskevat paitsi ohjelmistoja, myös niiden käyttöympäristöjä ja käyttäjiä sekä itse käsiteltävää tietoa: näitä mekanismeja ovat esimerkiksi tietoluokittelut, tietoon pääsyn rajaaminen, käyttäjäidentiteettien hallinta sekä salaustekniikat. Suojaustoimista huolimatta tietoturvaloukkaukset vaarantavat sekä liiketoiminnan ja yhteiskunnan strategisia tietovarantoj että henkilökohtaisia tietojamme. Taloudellisten menetysten lisäksi hyökkäykset murentavat luottamusta tietoturvan kulmakiviin: tiedon luottamuksellisuuteen, luotettavuuteen ja sen saatavuuteen. Näiden tietoturvan perustusten suojaamiseksi on laadittu kasvava määrä tietoturvaa koskevia säädöksiä, jotka määrittävät tietoturvan perustason. Lisääntyneen tietoturvatietoisuuden ansiosta uusi säännöstö on ulotettu koskemaan myös turvatun tietojenkäsittelyn ydintä,ohjelmistokehitystä. Tietoturva koostuu useista osa-alueista. Näitä ovat organisaatiotason tietoturvakäytännöt, tietojenkäsittelyinfrastruktuurin tietoturva, sekä tämän tutkimuksen kannalta keskeisenä osana ohjelmistojen tietoturva. Tähän osaalueeseen sisältyvät ohjelmistojen kehittämisen aikana käytettävät tietoturvatekniikat ja -prosessit. Tarkoituksena on vähentää ohjelmistojen organisaatioille aiheuttamia riskejä, tai poistaa ne kokonaan. Ohjelmistokehityksen tietoturva pyrkii pienentämään ohjelmistojen elinkaarikustannuksia määrittämällä ja toteuttamalla tietoturvakontrolleja suoraan ohjelmistoon itseensä. Lisäksi kontrollien toimivuus ja tehokkuus osoitetaan erillisten verifiointija validointimenetelmien avulla. Tämä väitöskirjatutkimus keskittyy tietoturvatyöhön osana iteratiivista ja inkrementaalista ns. ketterää (agile) ohjelmistokehitystä. Tutkimuksen tavoitteena on löytää uusia tapoja tuottaa tietoturvallisia ohjelmistoja liittämällä tietoturvatyö kiinteäksi osaksi ohjelmistokehityksen prosesseja. Tietoturvatyön prosessit on johdettu alan tieteellisestä ja teknillisestä kirjallisuudesta, ohjelmistokehitystyön vallitsevista käytännöistä sekä kansallisista ja kansainvälisistä tietoturvastandardeista. Standardoitujen tietoturvavaatimusten kehitystä on seurattu aina niiden alkuajoilta 1960-luvulta lähtien, liittäen ne ohjelmistokehityksen tavoitteiden ja haasteiden kehitykseen: nykyaikaan ja ketterien menetelmien valtakauteen saakka. Tutkimuksessa esitetään konkreettisia ratkaisuja ohjelmistokehityksen tietoturvatyön tavoitteiden asettamiseen ja niiden saavuttamiseen. Tutkimuksessa myös tunnistetaan ongelmia ja haasteita tietoturvatyön ja ohjelmistokehityksen menetelmien yhdistämisessä, joiden ratkaisemiseksi tarjotaan toimintaohjeita ja -vaihtoehtoja. Tutkimuksen perusteella iteratiivisen ja inkrementaalisen ohjelmistokehityksen käytäntöjen ja periaatteiden yhteensovittaminen tietoturvatyön toimintojen kanssa parantaa ohjelmistojen laatua ja tietoturvaa, alentaen täten kustannuksia koko ohjelmiston ylläpitoelinkaaren aikana. Ohjelmistokehitystyön automatisointi, työkaluihin pohjautuvat prosessit ja pyrkimys tehokkuuteen sekä korkeaan laatuun ovat suoraan yhtenevät tietoturvatyön menetelmien ja tavoitteiden kanssa. Tutkimuksessa tunnistettiin useita uusia tapoja yhdistää ohjelmistokehitys ja tietoturvatyö. Lisäksi on löydetty tapoja käyttää dokumentointiin, analyyseihin ja katselmointeihin perustuvaa tietoturvan todentamiseen tuotettavaa materiaalia osana ohjelmistojen suunnittelua ja laadunvarmistusta. Erillisinä nämä prosessit johtavat tilanteeseen, jossa tietoturvamateriaalia hyödynnetään pelkästään ohjelmistokehityksen ulkopuolisiin tarpeisiin. Tutkimustulokset hyödyttävät kaikkia sidosryhmiä ohjelmistojen kehittäjistä niiden tilaajiin ja loppukäyttäjiin. Ohjelmistojen tietoturvatyö perustuu tietoon ja koulutukseen. Tieto puolestaan lisää kysyntää, joka luo tietoturvatyölle konkreettiset tavoitteet ja perustelut jo ohjelmistokehitysvaiheessa. Tietoturvatyön painopiste siirtyy torjunnasta ja vahinkojen korjauksesta kohti vahinkojen rakenteellista ehkäisyä. Kysyntä luo tarpeen myös uusille työkaluille, prosesseille ja tekniikoille, joilla lisätään tietoturvatyön tehokkuutta ja vaikuttavuutta. Tällä hetkellä kysyntää luovat lähinnä lisääntyneet tietoturvaa koskevat säädökset. Pääosa muutostarpeesta syntyy kuitenkin ohjelmistojen tilaajien ja käyttäjien vaatimuksista: ohjelmistojen tietoturvakyvykkyyden taloudellinen merkitys kasvaa. Tietoturvan tärkeys tulee korostumaan entisestään, lisäten tarvetta tietoturvatyölle ja tutkimukselle myös tulevaisuudessa

Photonic wideband phased array: an optical time steered antenna based on a new true time delay unit

L’attività di ricerca svolta durante il corso di dottorato e descritta dettagliatamente all’interno della tesi è stata diretta al progetto di una innovativa rete ottica di formazione del fascio per antenne a schiera a banda larga esenti dal fenomeno del beam squint. La rete di formazione del fascio proposta è basata sull’utilizzo di un chip ottico integrato modulare che consente di realizzare il True Time Delay implementando switched delay lines. Le caratteristiche del sistema ne consentono l’utilizzo in architetture ad array e a subarray, e la sua modularità rende possibile, in principio, il pilotaggio del sistema radiante, integrando in un unico componente le linee di ritardo di ciascun elemento della schiera. Nella sua prima parte la tesi di dottorato introduce alle antenne ad alte prestazioni richieste dalle moderne applicazioni, focalizzando l’attenzione sui Phased Array, sistemi radianti destinati a svolgere un ruolo di primo piano grazie alla loro flessibilità e potenzialità. Un’analisi ragionata delle soluzioni proposte in letteratura viene, quindi, proposta al fine di evidenziare i principi di funzionamento e le principali problematiche connesse all’implementazione di reti ottiche di formazione del fascio. Inoltre, vengono descritte e discusse le architetture ottiche utilizzate sia per il controllo della fase che per il controllo del ritardo. Successivamente viene presentata la nuova unità ottica integrata di tipo True Time Delay. Le configurazioni di utilizzo del chip ottico studiate e messe a punto durante gli anni del corso di dottorato vengono presentate nel dettaglio, chiarendo le scelte e le strategie di progetto utilizzate in modo da ottimizzare le prestazioni del sistema. Viene presentato il progetto di un prototipo di antenna a schiera basato sul nuovo modulo True Time Delay e un modello accurato dell’intero sistema, implementato allo scopo di verificare il funzionamento dell’antenna e determinarne le prestazioni. Il modello sviluppato tiene in conto delle reali caratteristiche dei dispositivi disponibili in commercio da utilizzarsi all’interno della rete e del sistema radiante, degli inevitabili errori realizzativi relativi a ciascun componente e delle caratteristiche peculiari del nuovo modulo di ritardo. Per compensare gli effetti degli errori suddetti è stata prevista all’interno della rete un’unità di compensazione. Per rendere semplice ed efficace determinarne i parametri è stato sviluppato un algoritmo evolutivo capace di sfruttare al meglio le potenzialità dell’unità così da evitare inutili complessità. Infine, viene proposta una nuova architettura, interamente ottica, di una rete di formazione del fascio per antenne a schiera capaci di irradiare sia fasci somma che fasci differenza beam squint free

System Level Performance Evaluation of Distributed Embedded Systems

In order to evaluate the feasibility of the distributed embedded systems in different application domains at an early phase, the System Level Performance Evaluation (SLPE) must provide reliable estimates of the nonfunctional properties of the system such as end-to-end delays and packet losses rate. The values of these non-functional properties depend not only on the application layer of the OSI model but also on the technologies residing at the MAC, transport and Physical layers. Therefore, the system level performance evaluation methodology must provide functionally accurate models of the protocols and technologies operating at these layers. After conducting a state of the art survey, it was found that the existing approaches for SLPE are either specialized for a particular domain of systems or apply a particular model of computation (MOC) for modeling the communication and synchronization between the different components of a distributed application. Therefore, these approaches abstract the functionalities of the data-link, Transport and MAC layers by the highly abstract message passing methods employed by the different models of computation. On the other hand, network simulators such as OMNeT++, ns-2 and Opnet do not provide the models for platform components of devices such as processors and memories and totally abstract the application processing by delays obtained via traffic generators. Therefore the system designer is not able to determine the potential impact of an application in terms of utilization of the platform used by the device. Hence, for a system level performance evaluation approach to estimate both the platform utilization and the non-functional properties which are a consequence of the lower layers of OSI models (such as end-to-end delays), it must provide the tools for automatic workload extraction of application workload models at various levels of refinement and functionally correct models of lower layers of OSI model (Transport MAC and Physical layers). Since ABSOLUT is not restricted to a particular domain and also does not depend on any MOC, therefore it was selected for the extension to a system level performance evaluation approach for distributed embedded systems. The models of data-link and Transport layer protocols and automatic workload generation of system calls was not available in ABSOLUT performance evaluation methodology. The, thesis describes the design and modelling of these OSI model layers and automatic workload generation tool for system calls. The tools and models integrated to ABSOLUT methodology were used in a number of case studies. The accuracy of the protocols was compared to network simulators and real systems. The results were 88% accurate for user space code of the application layer and provide an improvement of over 50% as compared to manual models for external libraries and system calls. The ABSOLUT physical layer models were found to be 99.8% accurate when compared to analytical models. The MAC and transport layer models were found to be 70-80% accurate when compared with the same scenarios simulated by ns-2 and OMNeT++ simulators. The bit error rates, frame error probability and packet loss rates show close correlation with the analytical methods .i.e., over 99%, 92% and 80% respectively. Therefore the results of ABSOLUT framework for application layer outperform the results of performance evaluation approaches which employ virtual systems and at the same time provide as accurate estimates of the end-to-end delays and packet loss rate as network simulators. The results of the network simulators also vary in absolute values but they follow the same trend. Therefore, the extensions made to ABSOLUT allow the system designer to identify the potential bottlenecks in the system at different OSI model layers and evaluate the non-functional properties with a high level of accuracy. Also, if the system designer wants to focus entirely on the application layer, different models of computations can be easily instantiated on top of extended ABSOLUT framework to achieve higher simulation speeds as described in the thesis

DIVAS: An LLM-based End-to-End Framework for SoC Security Analysis and Policy-based Protection

Securing critical assets in a bus-based System-On-Chip (SoC) is imperative to mitigate potential vulnerabilities and prevent unauthorized access, ensuring the integrity, availability, and confidentiality of the system. Ensuring security throughout the SoC design process is a formidable task owing to the inherent intricacies in SoC designs and the dispersion of assets across diverse IPs. Large Language Models (LLMs), exemplified by ChatGPT (OpenAI) and BARD (Google), have showcased remarkable proficiency across various domains, including security vulnerability detection and prevention in SoC designs. In this work, we propose DIVAS, a novel framework that leverages the knowledge base of LLMs to identify security vulnerabilities from user-defined SoC specifications, map them to the relevant Common Weakness Enumerations (CWEs), followed by the generation of equivalent assertions, and employ security measures through enforcement of security policies. The proposed framework is implemented using multiple ChatGPT and BARD models, and their performance was analyzed while generating relevant CWEs from the SoC specifications provided. The experimental results obtained from open-source SoC benchmarks demonstrate the efficacy of our proposed framework.Comment: 15 pages, 7 figures, 8 table

Applying Formal Methods to Networking: Theory, Techniques and Applications

Despite its great importance, modern network infrastructure is remarkable for the lack of rigor in its engineering. The Internet which began as a research experiment was never designed to handle the users and applications it hosts today. The lack of formalization of the Internet architecture meant limited abstractions and modularity, especially for the control and management planes, thus requiring for every new need a new protocol built from scratch. This led to an unwieldy ossified Internet architecture resistant to any attempts at formal verification, and an Internet culture where expediency and pragmatism are favored over formal correctness. Fortunately, recent work in the space of clean slate Internet design---especially, the software defined networking (SDN) paradigm---offers the Internet community another chance to develop the right kind of architecture and abstractions. This has also led to a great resurgence in interest of applying formal methods to specification, verification, and synthesis of networking protocols and applications. In this paper, we present a self-contained tutorial of the formidable amount of work that has been done in formal methods, and present a survey of its applications to networking.Comment: 30 pages, submitted to IEEE Communications Surveys and Tutorial