High-level Cryptographic Abstractions

The interfaces exposed by commonly used cryptographic libraries are clumsy, complicated, and assume an understanding of cryptographic algorithms. The challenge is to design high-level abstractions that require minimum knowledge and effort to use while also allowing maximum control when needed. This paper proposes such high-level abstractions consisting of simple cryptographic primitives and full declarative configuration. These abstractions can be implemented on top of any cryptographic library in any language. We have implemented these abstractions in Python, and used them to write a wide variety of well-known security protocols, including Signal, Kerberos, and TLS. We show that programs using our abstractions are much smaller and easier to write than using low-level libraries, where size of security protocols implemented is reduced by about a third on average. We show our implementation incurs a small overhead, less than 5 microseconds for shared key operations and less than 341 microseconds (< 1%) for public key operations. We also show our abstractions are safe against main types of cryptographic misuse reported in the literature

An Overview of Cryptography (Updated Version, 3 March 2016)

There are many aspects to security and many applications, ranging from secure commerce and payments to private communications and protecting passwords. One essential aspect for secure communications is that of cryptography...While cryptography is necessary for secure communications, it is not by itself sufficient. This paper describes the first of many steps necessary for better security in any number of situations. A much shorter, edited version of this paper appears in the 1999 edition of Handbook on Local Area Networks published by Auerbach in September 1998

Multi-party authentication protocols for web services

The Web service technology allows the dynamic composition of a workflow (or a business flow) by composing a set of existing Web services scattered across the Internet. While a given Web service may have multiple service instances taking part in several workflows simultaneously, a workflow often involves a set of service instances that belong to different Web services. In order to establish trust relationships amongst service instances, new security protocols are urgently needed. Hada and Maruyama [HAD02] presented a session-oriented, multi-party authentication protocol to resolve this problem. Within a session the protocol provides a common session secret shared by all the service instances, thereby distinguishing the instances from those of other sessions. However, individual instances cannot be distinguished and identified by the session secret. This leads to vulnerable session management and poor threat containment. In this thesis, we present a new design for a multi-party authentication protocol. In this protocol, each service instance is provided with a unique identifier. The Diffie-Hellman Key Agreement scheme is employed to generate the trust relationship between service instances within the same flow. The Coordinated Atomic Action scheme is exploited for achieving an improved level of threat containment. The new protocol was implemented in Java and evaluated by a combined use of experiments and model-based analysis. The results show that the time consumption for multi-party authentication increases linearly as the number of service instances that are introduced into a session increases. Our solution is therefore potentially applicable for Web service flow with a large number of participants. Various public key algorithms are also compared and evaluated during the experiments in order to select the most suitable one for our new protocol

Towards a model for ensuring optimal interoperability between the security systems of trading partners in a business-to-business e-commerce context

A vast range of controls/countermeasures exists for implementing security on information systems connected to the Internet. For the practitioner attempting to implement an integrated solution between trading partners operating across the Internet, this has serious implications in respect of interoperability between the security systems of the trading partners. The problem is exacerbated by the range of specification options within each control. This research is an attempt to find a set of relevant controls and specifications towards a framework for ensuring optimal interoperability between trading partners in this context. Since a policy-based, layered approach is advocated, which allows each trading partner to address localized risks independently, no exhaustive risk analysis is attempted. The focus is on infrastructure that is simultaneously optimally secure and provides optimal interoperability. It should also be scalable, allowing for additional security controls to be added whenever deemed necessary.ComputingM. Sc. (Information Systems

Authentication Protocols and Privacy Protection

Tato dizertační práce se zabývá kryptografickými prostředky pro autentizaci. Hlavním tématem však nejsou klasické autentizační protokoly, které nabízejí pouze ověření identity, ale tzv. atributové autentizační systémy, pomocí kterých mohou uživatelé prokazovat svoje osobní atributy. Tyto atributy pak mohou představovat jakékoliv osobní informace, např. věk, národnost či místo narození. Atributy mohou být prokazovány anonymně a s podporou mnoha funkcí na ochranu digitální identity. Mezi takové funkce patří např. nespojitelnost autentizačních relací, nesledovatelnost, možnost výběru prokazovaných atributů či efektivní revokace. Atributové autentizační systémy jsou již nyní považovány za nástupce současných systémů v oficiálních strategických plánech USA (NSTIC) či EU (ENISA). Část požadovaných funkcí je již podporována existujícími kryptografickými koncepty jako jsou U-Prove či idemix. V současné době však není známý systém, který by poskytoval všechny potřebné funkce na ochranu digitální identity a zároveň byl prakticky implementovatelný na zařízeních, jako jsou čipové karty. Mezi klíčové slabiny současných systémů patří především chybějící nespojitelnost relací a absence revokace. Není tak možné efektivně zneplatnit zaniklé uživatele, ztracené či ukradené autentizační karty či karty škodlivých uživatelů. Z těchto důvodů je v této práci navrženo kryptografické schéma, které řeší slabiny nalezené při analýze existujících řešení. Výsledné schéma, jehož návrh je založen na ověřených primitivech, jako jsou $\Sigma$-protokoly pro důkazy znalostí, kryptografické závazky či ověřitelné šifrování, pak podporuje všechny požadované vlastnosti pro ochranu soukromí a digitální identity. Zároveň je však návrh snadno implementovatelný v prostředí smart-karet. Tato práce obsahuje plný kryptografický návrh systému, formální ověření klíčových vlastností, matematický model schématu v programu Mathematica pro ověření funkčnosti a výsledky experimentální implementace v prostředí .NET smart-karet. I přesto, že navrhovaný systém obsahuje podporu všech funkcí na ochranu soukromí, včetně těch, které chybí u existujících systémů, jeho výpočetní složitost zůstává stejná či nižší, doba ověření uživatele je tedy kratší než u existujících systémů. Výsledkem je schéma, které může velmi znatelně zvýšit ochranu soukromí uživatelů při jejich ověřování, především při využití v elektronických dokladech, přístupových systémech či Internetových službách.This dissertation thesis deals with the cryptographic constructions for user authentication. Rather than classical authentication protocols which allow only the identity verification, the attribute authentication systems are the main topic of this thesis. The attribute authentication systems allow users to give proofs about the possession of personal attributes. These attributes can represent any personal information, for example age, nationality or birthplace. The attribute ownership can be proven anonymously and with the support of many features for digital identity protection. These features include, e.g., the unlinkability of verification sessions, untraceability, selective disclosure of attributes or efficient revocation. Currently, the attribute authentication systems are considered to be the successors of existing authentication systems by the official strategies of USA (NSTIC) and EU (ENISA). The necessary features are partially provided by existing cryptographic concepts like U-Prove and idemix. But at this moment, there is no system providing all privacy-enhancing features which is implementable on computationally restricted devices like smart-cards. Among all weaknesses of existing systems, the missing unlinkability of verification sessions and the absence of practical revocation are the most critical ones. Without these features, it is currently impossible to invalidate expired users, lost or stolen authentication cards and cards of malicious users. Therefore, a new cryptographic scheme is proposed in this thesis to fix the weaknesses of existing schemes. The resulting scheme, which is based on established primitives like $\Sigma$-protocols for proofs of knowledge, cryptographic commitments and verifiable encryption, supports all privacy-enhancing features. At the same time, the scheme is easily implementable on smart-cards. This thesis includes the full cryptographic specification, the formal verification of key properties, the mathematical model for functional verification in Mathematica software and the experimental implementation on .NET smart-cards. Although the scheme supports all privacy-enhancing features which are missing in related work, the computational complexity is the same or lower, thus the time of verification is shorter than in existing systems. With all these features and properties, the resulting scheme can significantly improve the privacy of users during their verification, especially when used in electronic ID systems, access systems or Internet services.

Multiprotocol Authentication Device for HPC and Cloud Environments Based on Elliptic Curve Cryptography

Multifactor authentication is a relevant tool in securing IT infrastructures combining two or more credentials. We can find smartcards and hardware tokens to leverage the authentication process, but they have some limitations. Users connect these devices in the client node to log in or request access to services. Alternatively, if an application wants to use these resources, the code has to be amended with bespoke solutions to provide access. Thanks to advances in system-on-chip devices, we can integrate cryptographically robust, low-cost solutions. In this work, we present an autonomous device that allows multifactor authentication in client–server systems in a transparent way, which facilitates its integration in High-Performance Computing (HPC) and cloud systems, through a generic gateway. The proposed electronic token (eToken), based on the system-on-chip ESP32, provides an extra layer of security based on elliptic curve cryptography. Secure communications between elements use Message Queuing Telemetry Transport (MQTT) to facilitate their interconnection. We have evaluated different types of possible attacks and the impact on communications. The proposed system offers an efficient solution to increase security in access to services and systems.Spanish Ministry of Science, Innovation and Universities (MICINN) PGC2018-096663-B-C44European Union (EU

Application level security enforcement mechanisms for advanced network services

Masteroppgave i informasjons- og kommunikasjonsteknologi 2006 - Høgskolen i Agder, GrimstadToday the telecom world and the Internet world are converging. Ericsson has foreseen this convergence and developed a prototype of a service creation and execution environment called ServiceFrame. ServiceFrame is an extension of the ActorFrame framework. ActorFrame features new concepts described in UML 2.0, such as connectors, ports, parts and behaviour inheritance and structured classes. ActorFrame has central components called actors and agents. Actors and agents are modelled and described using the UML 2.0 notation. In ActorFrame and ServiceFrame actors and agents are communicating asynchronously using messages and concurrent state machines. The ServiceFrame developers have always concentrated on making ServiceFrame a framework with distributed components. The developers have not yet focused on the security issues in ServiceFrame. As a result ServiceFrame currently has no security mechanisms for securing actors or agents. This thesis proposes a security protocol and security mechanisms for securing ServiceFrame. The proposed security mechanisms are implemented in a prototype and tested using a test case. The report first gives an introduction to security concepts, such as authentication, authorisation, integrity and confidentiality. The report also describes relevant frameworks and security protocols. The Java programming language is used for developing and implementing the security mechanisms. UML 2.0 is used as the modelling language. At the end of the report the security mechanisms are analysed and discussed. Authentication in ServiecFrame is achieved by using a key exchange protocol with certificates. In the thesis a solution for achieving authorisation is proposed. This thesis only proposes a rudimentary solution which uses access control lists. Integrity and confidentiality are achieved using cryptography and signing of messages. The main conclusion of this thesis is that the security mechanisms proposed can contribute to securing the ServiceFrame framework. The security mechanisms achieve point to point security between two agents. ServiceFrame could be used to secure access to the Parlay gateway and telecom services. Fundamental in the security mechanisms is an extended variant of the Needham-Schroeder-Lowe public key protocol. The main contribution of this thesis has been to introduce security in ServiceFrame, which previously had not been implemented. The security mechanisms can be used by developers of ServiceFrame to accomplish security in their services. Commercial systems require focus on security to secure both end users and the service providers. The thesis work may contribute to the establishment of ServiceFrame in commercially related products in the future. The thesis has shown that ServiceFrame does not have security mechanisms and that achieving security is essential for ServiceFrame. The thesis has also shown that some of the proposed security mechanisms can be implemented in the framework. It has also shown how security concepts can be implemented and used by distributed components