Lightweight password hashing scheme for embedded systems

Passwords constitute the main mean for authentication in computer systems. In order to maintain the user-related information at the service provider end, password hashing schemes (PHS) are utilized. The limited and old-fashioned solutions led the international cryptographic community to conduct the Password Hashing Competition (PHC). The competition will propose a small portfolio of schemes suitable for widespread usage until 2015. Embedded systems form a special application domain, utilizing devices with inherent computational limitations. Lightweight cryptography focuses in designing schemes for such devices and targets moderate levels of security. In this paper, a lightweight poly PHS suitable for lightweight cryptography is presented. At first, we design two lightweight versions of the PHC schemes Catena and PolyPassHash. Then, we integrate them and implement the proposed scheme – called LightPolyPHS. A fair comparison with similar proposals on mainstream computer is presented

Why Do Developers Get Password Storage Wrong? A Qualitative Usability Study

Passwords are still a mainstay of various security systems, as well as the cause of many usability issues. For end-users, many of these issues have been studied extensively, highlighting problems and informing design decisions for better policies and motivating research into alternatives. However, end-users are not the only ones who have usability problems with passwords! Developers who are tasked with writing the code by which passwords are stored must do so securely. Yet history has shown that this complex task often fails due to human error with catastrophic results. While an end-user who selects a bad password can have dire consequences, the consequences of a developer who forgets to hash and salt a password database can lead to far larger problems. In this paper we present a first qualitative usability study with 20 computer science students to discover how developers deal with password storage and to inform research into aiding developers in the creation of secure password systems

A Newfangled Authentication Protocol Based On Audio Produced Principles

Graphical authentication is more proficient and more securable. An imperative convenience objective for information based authentication frameworks is to bolster client in selecting passwords for higher security in the feeling of being from an extended viable security space. Here we are utilizing x and y directions to pick a photo secret word. Also the photos in x and y directions are changing haphazardly and subsequently it is hard to locate the first picture. In our base paper the methodologies utilized are "Convincing signaled snap focuses"," Cued snap focuses" and "Pass focuses". Primary apparatuses utilized here are pccp, viewport and that is utilized for secret word creation. Viewport methodologies are utilized to significant client picked secret word and secure framework created arbitrary watchword that are hard to recollect. The pccp making a less guessable secret key is the least demanding game-plan. With a specific end goal to dodge "Shoulder surfing" calculation we are going for AES (Advanced encryption standard). In a contemporary mastery, the customary Authentication methodologies like "alphanumeric - usernames and passwords" can't be a versatile secured technique as it make out a critical downsides. It can't be protected and sound from programmers. Graphical passwords are a different option for existing alphanumeric passwords. In Graphical passwords clients click on pictures than sort a long, complex secret key. Exhaustive examination is finished by different analysts proposes that the photo's majority based authentication plans are essentially delicate as client tends to tap on hotspots in the pictures. A hotspot is the picture's territory which is effectively perceived against every single other picture, accordingly making such strategies defenseless. To make greater from the available confirmation, another convention "in light of the sound time stamps" making it hard for the shams to perform mystery. Here is a novel one of a kind answer for graphical validation defining so as To take into account sound time stamps another method for model called "A NEWFANGLED AUTHENTICATION PROTOCOL BASED ON AUDIO PRODUCED PRINCIPLES ". This model calls a sound time stamps and in addition the number of sound timestamps and scramble the secret word with message digest adaptation 5 and making it hard for the gatecrasher to break the watchword there by forcing the more elevated amounts of security to the framework. The gatecrasher can't get the time stamps and additionally check of time stamps and making this strategy more secure, dependable and difficult to figure

Design and Analysis of Cryptographic Algorithms for Authentication

During the previous decades, the upcoming demand for security in the digital world, e.g., the Internet, lead to numerous groundbreaking research topics in the field of cryptography. This thesis focuses on the design and analysis of cryptographic primitives and schemes to be used for authentication of data and communication endpoints, i.e., users. It is structured into three parts, where we present the first freely scalable multi-block-length block-cipher-based compression function (Counter-bDM) in the first part. The presented design is accompanied by a thorough security analysis regarding its preimage and collision security. The second and major part is devoted to password hashing. It is motivated by the large amount of leaked password during the last years and our discovery of side-channel attacks on scrypt – the first modern password scrambler that allowed to parameterize the amount of memory required to compute a password hash. After summarizing which properties we expect from a modern password scrambler, we (1) describe a cache-timing attack on scrypt based on its password-dependent memory-access pattern and (2) outline an additional attack vector – garbage-collector attacks – that exploits optimization which may disregard to overwrite the internally used memory. Based on our observations, we introduce Catena – the first memory-demanding password-scrambling framework that allows a password-independent memory-access pattern for resistance to the aforementioned attacks. Catena was submitted to the Password Hashing Competition (PHC) and, after two years of rigorous analysis, ended up as a finalist gaining special recognition for its agile framework approach and side-channel resistance. We provide six instances of Catena suitable for a variety of applications. We close the second part of this thesis with an overview of modern password scramblers regarding their functional, security, and general properties; supported by a brief analysis of their resistance to garbage-collector attacks. The third part of this thesis is dedicated to the integrity (authenticity of data) of nonce-based authenticated encryption schemes (NAE). We introduce the so-called j-IV-Collision Attack, allowing to obtain an upper bound for an adversary that is provided with a first successful forgery and tries to efficiently compute j additional forgeries for a particular NAE scheme (in short: reforgeability). Additionally, we introduce the corresponding security notion j-INT-CTXT and provide a comparative analysis (regarding j-INT-CTXT security) of the third-round submission to the CAESAR competition and the four classical and widely used NAE schemes CWC, CCM, EAX, and GCM.Die fortschreitende Digitalisierung in den letzten Jahrzehnten hat dazu geführt, dass sich das Forschungsfeld der Kryptographie bedeutsam weiterentwickelt hat. Diese, im Wesentlichen aus drei Teilen bestehende Dissertation, widmet sich dem Design und der Analyse von kryptographischen Primitiven und Modi zur Authentifizierung von Daten und Kommunikationspartnern. Der erste Teil beschäftigt sich dabei mit blockchiffrenbasierten Kompressionsfunktionen, die in ressourcenbeschränkten Anwendungsbereichen eine wichtige Rolle spielen. Im Rahmen dieser Arbeit präsentieren wir die erste frei skalierbare und sichere blockchiffrenbasierte Kompressionsfunktion Counter-bDM und erweitern somit flexibel die erreichbare Sicherheit solcher Konstruktionen. Der zweite Teil und wichtigste Teil dieser Dissertation widmet sich Passwort-Hashing-Verfahren. Zum einen ist dieser motiviert durch die große Anzahl von Angriffen auf Passwortdatenbanken großer Internet-Unternehmen. Zum anderen bot die Password Hashing Competition (PHC) die Möglichkeit, unter Aufmerksamkeit der Expertengemeinschaft die Sicherheit bestehender Verfahren zu hinterfragen, sowie neue sichere Verfahren zu entwerfen. Im Rahmen des zweiten Teils entwarfen wir Anforderungen an moderne Passwort-Hashing-Verfahren und beschreiben drei Arten von Seitenkanal-Angriffen (Cache-Timing-, Weak Garbage-Collector- und Garbage-Collector-Angriffe) auf scrypt – das erste moderne Password-Hashing-Verfahren welches erlaubte, den benötigten Speicheraufwand zur Berechnung eines Passworthashes frei zu wählen. Basierend auf unseren Beobachtungen und Angriffen, stellen wir das erste moderne PasswordHashing-Framework Catena vor, welches für gewählte Instanzen passwortunabhängige Speicherzugriffe und somit Sicherheit gegen oben genannte Angriffe garantiert. Catena erlangte im Rahmen des PHC-Wettbewerbs besondere Anerkennung für seine Agilität und Resistenz gegen SeitenkanalAngriffe. Wir präsentieren sechs Instanzen des Frameworks, welche für eine Vielzahl von Anwendungen geeignet sind. Abgerundet wird der zweite Teil dieser Arbeit mit einem vergleichenden Überblick von modernen Passwort-Hashing-Verfahren hinsichtlich ihrer funktionalen, sicherheitstechnischen und allgemeinen Eigenschaften. Dieser Vergleich wird unterstützt durch eine kurze Analyse bezüglich ihrer Resistenz gegen (Weak) Garbage-Collector-Angriffe. Der dritte teil dieser Arbeit widmet sich der Integrität von Daten, genauer, der Sicherheit sogenannter Nonce-basierten authentisierten Verschlüsselungsverfahren (NAE-Verfahren), welche ebenso wie Passwort-Hashing-Verfahren in der heutigen Sicherheitsinfrastruktur des Internets eine wichtige Rolle spielen. Während Standard-Definitionen keine Sicherheit nach dem Fund einer ersten erfolgreich gefälschten Nachricht betrachten, erweitern wir die Sicherheitsanforderungen dahingehend wie schwer es ist, weitere Fälschungen zu ermitteln. Wir abstrahieren die Funktionsweise von NAEVerfahren in Klassen, analysieren diese systematisch und klassifizieren die Dritt-Runden-Kandidaten des CAESAR-Wettbewerbs, sowie vier weit verbreitete NAE-Verfahren CWC, CCM, EAX und GCM

Design and Analysis of Cryptographic Algorithms for Authentication

During the previous decades, the upcoming demand for security in the digital world, e.g., the Internet, lead to numerous groundbreaking research topics in the field of cryptography. This thesis focuses on the design and analysis of cryptographic primitives and schemes to be used for authentication of data and communication endpoints, i.e., users. It is structured into three parts, where we present the first freely scalable multi-block-length block-cipher-based compression function (Counter-bDM) in the first part. The presented design is accompanied by a thorough security analysis regarding its preimage and collision security. The second and major part is devoted to password hashing. It is motivated by the large amount of leaked password during the last years and our discovery of side-channel attacks on scrypt – the first modern password scrambler that allowed to parameterize the amount of memory required to compute a password hash. After summarizing which properties we expect from a modern password scrambler, we (1) describe a cache-timing attack on scrypt based on its password-dependent memory-access pattern and (2) outline an additional attack vector – garbage-collector attacks – that exploits optimization which may disregard to overwrite the internally used memory. Based on our observations, we introduce Catena – the first memory-demanding password-scrambling framework that allows a password-independent memory-access pattern for resistance to the aforementioned attacks. Catena was submitted to the Password Hashing Competition (PHC) and, after two years of rigorous analysis, ended up as a finalist gaining special recognition for its agile framework approach and side-channel resistance. We provide six instances of Catena suitable for a variety of applications. We close the second part of this thesis with an overview of modern password scramblers regarding their functional, security, and general properties; supported by a brief analysis of their resistance to garbage-collector attacks. The third part of this thesis is dedicated to the integrity (authenticity of data) of nonce-based authenticated encryption schemes (NAE). We introduce the so-called j-IV-Collision Attack, allowing to obtain an upper bound for an adversary that is provided with a first successful forgery and tries to efficiently compute j additional forgeries for a particular NAE scheme (in short: reforgeability). Additionally, we introduce the corresponding security notion j-INT-CTXT and provide a comparative analysis (regarding j-INT-CTXT security) of the third-round submission to the CAESAR competition and the four classical and widely used NAE schemes CWC, CCM, EAX, and GCM.Die fortschreitende Digitalisierung in den letzten Jahrzehnten hat dazu geführt, dass sich das Forschungsfeld der Kryptographie bedeutsam weiterentwickelt hat. Diese, im Wesentlichen aus drei Teilen bestehende Dissertation, widmet sich dem Design und der Analyse von kryptographischen Primitiven und Modi zur Authentifizierung von Daten und Kommunikationspartnern. Der erste Teil beschäftigt sich dabei mit blockchiffrenbasierten Kompressionsfunktionen, die in ressourcenbeschränkten Anwendungsbereichen eine wichtige Rolle spielen. Im Rahmen dieser Arbeit präsentieren wir die erste frei skalierbare und sichere blockchiffrenbasierte Kompressionsfunktion Counter-bDM und erweitern somit flexibel die erreichbare Sicherheit solcher Konstruktionen. Der zweite Teil und wichtigste Teil dieser Dissertation widmet sich Passwort-Hashing-Verfahren. Zum einen ist dieser motiviert durch die große Anzahl von Angriffen auf Passwortdatenbanken großer Internet-Unternehmen. Zum anderen bot die Password Hashing Competition (PHC) die Möglichkeit, unter Aufmerksamkeit der Expertengemeinschaft die Sicherheit bestehender Verfahren zu hinterfragen, sowie neue sichere Verfahren zu entwerfen. Im Rahmen des zweiten Teils entwarfen wir Anforderungen an moderne Passwort-Hashing-Verfahren und beschreiben drei Arten von Seitenkanal-Angriffen (Cache-Timing-, Weak Garbage-Collector- und Garbage-Collector-Angriffe) auf scrypt – das erste moderne Password-Hashing-Verfahren welches erlaubte, den benötigten Speicheraufwand zur Berechnung eines Passworthashes frei zu wählen. Basierend auf unseren Beobachtungen und Angriffen, stellen wir das erste moderne PasswordHashing-Framework Catena vor, welches für gewählte Instanzen passwortunabhängige Speicherzugriffe und somit Sicherheit gegen oben genannte Angriffe garantiert. Catena erlangte im Rahmen des PHC-Wettbewerbs besondere Anerkennung für seine Agilität und Resistenz gegen SeitenkanalAngriffe. Wir präsentieren sechs Instanzen des Frameworks, welche für eine Vielzahl von Anwendungen geeignet sind. Abgerundet wird der zweite Teil dieser Arbeit mit einem vergleichenden Überblick von modernen Passwort-Hashing-Verfahren hinsichtlich ihrer funktionalen, sicherheitstechnischen und allgemeinen Eigenschaften. Dieser Vergleich wird unterstützt durch eine kurze Analyse bezüglich ihrer Resistenz gegen (Weak) Garbage-Collector-Angriffe. Der dritte teil dieser Arbeit widmet sich der Integrität von Daten, genauer, der Sicherheit sogenannter Nonce-basierten authentisierten Verschlüsselungsverfahren (NAE-Verfahren), welche ebenso wie Passwort-Hashing-Verfahren in der heutigen Sicherheitsinfrastruktur des Internets eine wichtige Rolle spielen. Während Standard-Definitionen keine Sicherheit nach dem Fund einer ersten erfolgreich gefälschten Nachricht betrachten, erweitern wir die Sicherheitsanforderungen dahingehend wie schwer es ist, weitere Fälschungen zu ermitteln. Wir abstrahieren die Funktionsweise von NAEVerfahren in Klassen, analysieren diese systematisch und klassifizieren die Dritt-Runden-Kandidaten des CAESAR-Wettbewerbs, sowie vier weit verbreitete NAE-Verfahren CWC, CCM, EAX und GCM

Graphical Password Scheme Using Cued Click Point and Persuasion with Multiple Images

There are three main categories of authentication system – token-based (what you have), biometric-based (who you are) and knowledge-based (what you know). Cued Click Point is a graphical password scheme which is a type of knowledge based authentication. In CCP, user clicks on one point per picture for an arrangement of pictures.CCP gives more prominent security than PassPoints in light of the fact that the quantity of pictures builds the workload for attackers. The proposed system uses persuasion allowing user’s choice to a certain extent while encouraging users towards stronger and less-vulnerable passwords.In the proposed system, the undertaking of choosing less secure passwords (which are simple for attackers to hack) is more monotonous, disheartening users from settling on such decisions.In actuality, this approach makes picking a more secure secret key less weight on clients, it is less demanding to take after the framework's recommendations for a protected password—an element lacking in many systems. CCP is an effective alternative to text-based passwords and other forms of traditional authentication system. Psychological studies have also revealed that human mind can recognize images faster than text and numbers. CCP can be applied to a system front-end which requires high level of security.This paper presents implementation of Cued Click Point (CCP) graphical password which uses persuasion along with multiple images

Computationally Data-Independent Memory Hard Functions

Memory hard functions (MHFs) are an important cryptographic primitive that are used to design egalitarian proofs of work and in the construction of moderately expensive key-derivation functions resistant to brute-force attacks. Broadly speaking, MHFs can be divided into two categories: data-dependent memory hard functions (dMHFs) and data-independent memory hard functions (iMHFs). iMHFs are resistant to certain side-channel attacks as the memory access pattern induced by the honest evaluation algorithm is independent of the potentially sensitive input e.g., password. While dMHFs are potentially vulnerable to side-channel attacks (the induced memory access pattern might leak useful information to a brute-force attacker), they can achieve higher cumulative memory complexity (CMC) in comparison than an iMHF. In particular, any iMHF that can be evaluated in N steps on a sequential machine has CMC at most ?((N^2 log log N)/log N). By contrast, the dMHF scrypt achieves maximal CMC ?(N^2) - though the CMC of scrypt would be reduced to just ?(N) after a side-channel attack. In this paper, we introduce the notion of computationally data-independent memory hard functions (ciMHFs). Intuitively, we require that memory access pattern induced by the (randomized) ciMHF evaluation algorithm appears to be independent from the standpoint of a computationally bounded eavesdropping attacker - even if the attacker selects the initial input. We then ask whether it is possible to circumvent known upper bound for iMHFs and build a ciMHF with CMC ?(N^2). Surprisingly, we answer the question in the affirmative when the ciMHF evaluation algorithm is executed on a two-tiered memory architecture (RAM/Cache). We introduce the notion of a k-restricted dynamic graph to quantify the continuum between unrestricted dMHFs (k=n) and iMHFs (k=1). For any ? > 0 we show how to construct a k-restricted dynamic graph with k=?(N^(1-?)) that provably achieves maximum cumulative pebbling cost ?(N^2). We can use k-restricted dynamic graphs to build a ciMHF provided that cache is large enough to hold k hash outputs and the dynamic graph satisfies a certain property that we call "amenable to shuffling". In particular, we prove that the induced memory access pattern is indistinguishable to a polynomial time attacker who can monitor the locations of read/write requests to RAM, but not cache. We also show that when k=o(N^(1/log log N))then any k-restricted graph with constant indegree has cumulative pebbling cost o(N^2). Our results almost completely characterize the spectrum of k-restricted dynamic graphs

Overview of the Candidates for the Password Hashing Competition - And Their Resistance Against Garbage-Collector Attacks

In this work we provide an overview of the candidates of the Password Hashing Competition (PHC) regarding to their functionality, e.g., client-independent update and server relief, their security, e.g., memory-hardness and side-channel resistance, and its general proper- ties, e.g., memory usage and flexibility of the underlying primitives. Furthermore, we formally introduce two kinds of attacks, called Garbage- Collector and Weak Garbage-Collector Attack, exploiting the memory management of a candidate. Note that we consider all candidates which are not yet withdrawn from the competition

Quality of service technologies for multimedia applications in next generation networks

Next Generation Networks are constantly evolving towards solutions that allow the operator to provide advanced multimedia applications with QoS guarantees in heterogeneous, multi-domain and multi-services networks. Other than the unquestionable advantages inherent the ability to simultaneously handle traffic flows at different QoS levels, these architectures require management systems to efficiently perform quality guarantees and network resource utilization. These issues have been addressed in this thesis. DiffServ-aware Traffic Engineering (DS-TE) has been considered as reference architecture for the deployment of the quality management systems. It represents the most advanced technology to accomplish either network scalability and service granularity goals. On the basis of DS-TE features, a methodology for traffic and network resource management has been defined. It provides some rules for QoS service characterization and allows to implement Traffic Engineering policies with a class-based approach. A set of basic parameters for quality evaluation has been defined, that are the Key Performance Indicators; some mathematical model to derive the statistical nature of traffic have been analyzed and an algorithm to improve the fulfillment of quality of service targets and to optimize network resource utilization. It is aimed at reducing the complexity inherent the setting of some of the key parameters in the NGN architectures. Multidomain scenarios with technologies different from DS-TE have been also evaluated, defining some methodologies for network interoperability. Simulations with Opnet Modeler confirmed the efficacy of the proposed system in computing network configurations with QoS targets. With regard to QoS performance at the application level, video streaming applications in wireless domains have been particularly addressed. A rate control algorithm to adjust the rate on a per-window basis has been defined, making use of a short-term prediction of the network delay to keep the probability of playback buffer starvation lower than a desired threshold during each window. Finally, a framework for mutual authentication in web applications has been proposed and evaluated. It integrates an IBA password technique with a challenge-response scheme based on a shared secret key for image scrambling. The wireless environment is mainly addressed by the proposed system, which tries to overcome the severe constraints on security, data transmission capability and user friendliness imposed by such environment