Separating two roles of hashing in one-way message authentication

We analyse two new and related families of one-way authentication protocols, where a party wants to authenticate its public information to another. In the first, the objective is to do without shared passwords or a PKI, making use of low-bandwidth empirical/authentic channels where messages cannot be faked or modified. The analysis of these leads to a new security principle, termed separation of security concerns, under which protocols should be designed to tackle one-shot attacks and combinatorial search separately. This also leads us develop a new class of protocols for the case such as PKI where a relatively expensive signature mechanism exists. We demonstrate as part of this work that a popular protocol in the area, termed MANA I, neither optimises human effort nor offers as much security as had previously been believed. We offer a number of improved versions for MANA I that provides more security for half the empirical work, using a more general empirical channel

Quantum node portal- Devices and information management

An Internship in a European Company for developing a Web application-Domatica Global Solutions, Lisbon was undertaken to complete the Master’s Degree of Computer Engineering-Mobile Computing in the Polytechnic Institute of Leiria. The team Domatica deals with providing IoT solutions used for monitoring, controlling and collecting the data from the IoT gateways. The present work aims to develop a Web application for client’s side. The Web application named Quantum Node Portal is developed for the Devices and Information management. It provides access to the clients to their IoT gateways. Clients can monitor their devices, get various information, also can access the Portal for claiming their IoT gateways. The present work was developed using various technologies such as PHP framework named Laravel and several languages

블록체인 내 스마트 컨트랙트를 위한 데이터 리테일러 기반 분산형 오라클 디자인

학위논문 (석사)-- 서울대학교 대학원 : 공과대학 컴퓨터공학부, 2019. 2. 권태경.Smart contracts, a program that enables the automated execution of terms from the pre-defined condition establishment, became a core component of distributed applications (Dapps) leveraging the decentralized blockchain technology. Although many researchers keep trying adopting them to solve problems in the centralized systems such as the single point of failure (SPOF) and the need for excessive trust, there are multiple technical challenges in the practical use of them. Amongst the challenges, we focus on ``the oracle problem'' in this paper, which means how to feed external data with ensuring the trustworthiness to the smart contracts. There are two primary technical considerations: (1)how to make the smart contracts to access the external data (2)how can measure the reliability of the data. In this paper, we propose a useful oracle design and implementation with an investigation of target platforms and related works to analyze the technical requirements and available design choices. The proposed design focuses on the trustworthiness of the data sources by separating the roles of the data provider into ``publisher'' and ``retailer''. The former, the data sources, can gain rewards by publishing data on their networks, and the latter gains rewards by relaying the data to the target blockchain network. A reasonable incentive model motivates them to behave honestly to maintain the oracle stable. Consumer contracts can receive the resolved data from the multiple retailers by using the oracle deployed as an on-chain smart contract. In the case of data inconsistency, the proposed reputation-based data consensus protocol determines a value from the collected data pools. The selected retailers and publishers can gain rewards from the deposit pre-paid by the consumer contract, and the rejected ones get penalties. The main goal of this design is providing sufficient high-quality data to the blockchain by relieving the data sources' burden of participating in blockchain networks of potential consumers. The plenty of data supply may decrease the data price, that leads to great inter-operability between blockchain systems and the rest of the Internet. We also implement the protocols on Ethereum network and prove the practicality of the proposal in cost and time aspects, while most of the precedent researches are stuck with the protocol design. We expect that the design to contribute to the practical use of Dapps as the first working decentralized oracle through the code optimization process.스마트 컨트랙트는 입력 값이 사전에 약속된 조건을 만족하면 자동으로 계약을 이행하는 일종의 프로그램으로서, 분산 블록체인 기술의 발달과 함께 분산 어플리케이션(Distributed Applications, Dapps) 구현의 핵심 요소로 자리잡았다. 기존의 중앙화된 시스템에 존재했던 단일 장애점 문제, 과도한 신뢰 요구 등의 문제를 Dapp의 도입을 통해 해결하고자 하는 노력들이 계속되었음에도 불구하고, 기존 시스템을 대체할만한 수준의 솔루션을 구현하기 위해 해결해야 하는 기술적 난제들이 아직 상당수 존재한다. 본 논문에서는 이들 중 외부 데이터 연동 문제를 해결하기 위한 기법을 제안한다. 이러한 문제는 일반적으로 ``오라클 문제''로도 불리는데, 블록체인 내부에서 발생하는 데이터는 모두 검증 가능하므로 신뢰할 수 있는것에 비해 외부 네트워크에서 생성된 데이터의 신뢰성은 내부에서 보장할 수 없기 때문에 신뢰할 수 있을만한 데이터 공급처인 오라클을 어떻게 구현할 것인지에 대한 문제로 귀결된다. 오라클의 기술적 요구사항은 크게 두가지로 나누어 지는데, 외부 접근성이 없는 스마트 컨트랙트로 하여금 어떻게 외부 데이터에 접근할 수 있게 할 것인지에 대한 문제와, 해당 데이터의 신뢰성을 어떻게 보장할 것인지에 대한 문제가 함께 고려되어야 한다. 본 논문에서는 대표적인 스마트 컨트랙트 플랫폼 및 관련 서비스 분석을 통해 오라클 디자인에서 고려되어야 하는 특성들과 디자인 결정사항들을 도출하고 이를 기반으로 효과적인 오라클 디자인을 제안 및 구현하고자 하였다. 제안된 기법은 기존 관련 연구들과 달리 데이터 자체의 신뢰성에 집중하기 위해 외부의 데이터 ``발행자(Publisher)''와 이를 블록체인 네트워크로 전달하고 수수료를 얻는 ``리테일러(Retailer)''로 네트워크 참여자의 역할을 분리하고, 적절한 수익 배분 모델을 구성하여 이들로 하여금 정직한 활동을 유도함으로서 오라클 시스템을 동작케하도록 설계되었다. On-chain 스마트 컨트랙트로 배포된 오라클을 통해 소비자(Consumer) 컨트랙트는 원하는 정보를 다수의 리테일러로부터 전달받을 수 있다. 전달받은 데이터들이 값이 서로 다른 경우 이들은 발행자의 Reputation에 따른 가중치를 고려한 제안된 합의 프로토콜을 통해 신뢰할 수 있는 하나의 값으로 결정된다. 정직한 데이터를 제공한 발행자와 리테일러는 오라클을 통해 소비자가 미리 지불한 금액의 일부를 보상으로 획득할 수 있으며, 그렇지 않은 경우 합당한 패널티를 얻게 되어 향후 데이터 공급시 불이익을 받게 된다. 본 기법은 궁극적으로 데이터 발행자에게 보상을 지급하고 직접적인 블록체인 네트워크 참여 없이도 데이터를 발행할 수 있게 함으로써 기존 시스템들이 보유한 다수의 양질의 데이터가 안전하게 블록체인으로 공급될 수 있도록 설계되었다. 풍부한 데이터의 공급은 데이터 조달에 요구되는 비용의 감소를 통해 블록체인 네트워크와의 원활한 상호 운용성 보장으로 이어질 수 있다. 또한 현재까지 제안된 기법들이 주로 Whitepaper를 통한 아이디어 중심의 제안이거나 단순 분산 투표를 구현한 집단 지성 플랫폼인 것에 반해, 본 연구에서는 실질적인 데이터를 전달하는 오라클을 이더리움 네트워크에서 구현함으로서 제안된 모델이 실제 운용 가능하며 합당한 수준의 비용과 처리 시간으로 동작함을 증명하였다. 제안된 기법은 향후 내부 메모리 사용량과 연산량을 최소화하는 최적화 과정을 통해, 최초의 상용 분산 오라클 모델로서 더욱 실용적인 Dapp들의 구현에 기여할 수 있을 것으로 기대된다Chapter 1 Introduction 1 Chapter 2 Background 3 2.1 Smart Contract Platforms . . . . . . . . . . . . . . . . . . . . . . 3 2.1.1 Bitcoin . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1.2 Ethereum . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.1.3 EOS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.2 The Oracle Problem . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.3 Related Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.3.1 Oraclize . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.3.2 SchellingCoin . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.3.3 Augur . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.3.4 Witnet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Chapter 3 Design 10 3.1 Design Choices and Considerations . . . . . . . . . . . . . . . . . 10 3.1.1 Centralized vs. Decentralized . . . . . . . . . . . . . . . . 10 3.1.2 Architecture . . . . . . . . . . . . . . . . . . . . . . . . . 12 3.1.3 Service Scope . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.2 Design Proposal . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Chapter 4 Protocol 16 4.1 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 4.1.1 Request phase . . . . . . . . . . . . . . . . . . . . . . . . 17 4.1.2 Delivery Phase . . . . . . . . . . . . . . . . . . . . . . . . 18 4.1.3 Consensus Phase . . . . . . . . . . . . . . . . . . . . . . . 20 4.2 Data Structure and Authentication . . . . . . . . . . . . . . . . 20 4.3 Data Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 21 4.4 Data Delivery Tag . . . . . . . . . . . . . . . . . . . . . . . . . . 22 4.5 Incentive and Penalty . . . . . . . . . . . . . . . . . . . . . . . . 24 4.6 Data Consensus . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Chapter 5 Proof of Concept Implementation 27 5.1 Code . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 5.2 Evaluations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 5.2.1 Experimental environment . . . . . . . . . . . . . . . . . . 29 5.2.2 Transaction Cost and Processing Time . . . . . . . . . . 29 5.2.3 Practicality . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Chapter 6 Conclusion 34 Bibliography 35 요약 37Maste

TrusNet: Peer-to-Peer Cryptographic Authentication

Originally, the Internet was meant as a general purpose communication protocol, transferring primarily text documents between interested parties. Over time, documents expanded to include pictures, videos and even web pages. Increasingly, the Internet is being used to transfer a new kind of data which it was never designed for. In most ways, this new data type fits in naturally to the Internet, taking advantage of the near limit-less expanse of the protocol. Hardware protocols, unlike previous data types, provide a unique set security problem. Much like financial data, hardware protocols extended across the Internet must be protected with authentication. Currently, systems which do authenticate do so through a central server, utilizing a similar authentication model to the HTTPS protocol. This hierarchical model is often at odds with the needs of hardware protocols, particularly in ad-hoc networks where peer-to-peer communication is prioritized over a hierarchical model. Our project attempts to implement a peer-to-peer cryptographic authentication protocol to be used to protect hardware protocols extending over the Internet. The TrusNet project uses public-key cryptography to authenticate nodes on a distributed network, with each node locally managing a record of the public keys of nodes which it has encountered. These keys are used to secure data transmission between nodes and to authenticate the identities of nodes. TrusNet is designed to be used on multiple different types of network interfaces, but currently only has explicit hooks for Internet Protocol connections. As of June 2016, TrusNet has successfully achieved a basic authentication and communication protocol on Windows 7, OSX, Linux 14 and the Intel Edison. TrusNet uses RC-4 as its stream cipher and RSA as its public-key algorithm, although both of these are easily configurable. Along with the library, TrusNet also enables the building of a unit testing suite, a simple UI application designed to visualize the basics of the system and a build with hooks into the I/O pins of the Intel Edison allowing for a basic demonstration of the system

Gitek Bestill

Gitek Bestill is a system where the merchant will order bread from the bakers, who will then process these orders. The system has a calendar where all the placed orders can be seen, and running campaigns can be displayed. Shrinkage can be registered and a list can be viewed with the shrinkage of the different products. The bakers can add, delete and change products. A search for orders can be done by both merchants and bakers. Gitek Bestill has been developed in HTML, CSS, PHP, JavaScript/jQuery and MySQL.Gitek Bestill er et system for brødbestilling foretatt av kjøpmenn i Coop, og bakere som tar i mot disse bestillingene. Systemet har en kalenderoversikt hvor man ser plasserte ordre, og aktuelle kampanjer. Svinn på brød kan også registreres og man ser liste over brødene med svinn. Bakere har mulighet for å legge til, slette og endre produkter. Søk etter ordre finnes for både kjøpmenn og bakere. Gitek Bestill er utviklet i HTML, CSS, PHP, Javascript/ jQuery og MySQL.Gitek A

EEG/ERP Portal Security in New Technologies

Bezpečnost dat musí být zajištěna v EEG/ERP Portálu jak z technických, tak právních důvodů. Aplikace ukládá citlivé informace a musí být odolná proti neoprávněným akcím. Tato práce popisuje vylepšení bezpečnosti s použitím mechanismů zavedených v nových technologiích a pomocí odstraňování bezpečnostních slabin. Teoretická část zajišťuje uvedení do problematiky, popisuje jak právní aspekty, tak samotný projekt a principy zabezpečení. Poté je popsán proces migrace technologií, včetně nástrojů zavedených k umožnění tohoto kroku. Na základě analýzy bezpečnosti je poté přepracován proces autentizace a jsou opraveny nedostatky v autorizaci. Konečný stav je poté testován a vyhodnocen pro ověření způsobilosti portálu k veřejnému provozu.Katedra informatiky a výpočetní technikyObhájenoSecurity needs to be assured in EEG/ERP Portal for technical and legal reasons. The application stores sensitive data and has to be resistant against malicious actions. This thesis describes improving security by using features introduced in new technologies and by patching exploitable weaknesses. First, background information including legal aspects, project description and security principles are provided. Then the process of technology migration is described, including tools introduced to enable the transition. Following a security analysis, the authentication process is restructured and revealed authorization shortcomings are fixed. The final configuration is tested and evaluated to make sure the portal is suitable for wide use

Searchable Symmetric Encryption and its applications

In the age of personalized advertisement and online identity profiles, people’s personal information is worth more to corporations than ever. Storing data in the cloud is increasing in popularity due to bigger file sizes and people just storing more information digitally. The leading cloud storage providers require insight into what users store on their servers. This forces users to trust their cloud storage provider not to misuse their information. This opens the possibility that private information is sold to hackers or is made publicly available on the internet. However, the more realistic case is that the service provider sells or misuses your metadata for use in personalized advertisements or other, less apparent purposes. This thesis will explore Searchable Sym- metric Encryption (SSE) algorithms and how we can utilize them to make a more secure cloud storage serviceMasteroppgave i informatikkINF399MAMN-PROGMAMN-IN

Greenpass Client Tools for Delegated Authorization in Wireless Networks

Dartmouth\u27s Greenpass project seeks to provide strong access control to a wireless network while simultaneously providing flexible guest access; to do so, it augments the Wi-Fi Alliance\u27s existing WPA standard, which offers sufficiently strong user authentication and access control, with authorization based on SPKI certificates. SPKI allows certain local users to delegate network access to guests by issuing certificates that state, in essence, he should get access because I said it\u27s okay. The Greenpass RADIUS server described in Kim\u27s thesis [55] performs an authorization check based on such statements so that guests can obtain network access without requiring a busy network administrator to set up new accounts in a centralized database. To our knowledge, Greenpass is the first working delegation-based solution to Wi-Fi access control. My thesis describes the Greenpass client tools, which allow a guest to introduce himself to a delegator and allow the delegator to issue a new SPKI certificate to the guest. The guest does not need custom client software to introduce himself or to connect to the Wi-Fi network. The guest and delegator communicate using a set of Web applications. The guest obtains a temporary key pair and X.509 certificate if needed, then sends his public key value to a Web server we provide. The delegator looks up her guest\u27s public key and runs a Java applet that lets her verify her guests\u27 identity using visual hashing and issue a new SPKI certificate to him. The guest\u27s new certificate chain is stored as an HTTP cookie to enable him to push it to an authorization server at a later time. I also describe how Greenpass can be extended to control access to a virtual private network (VPN) and suggest several interesting future research and development directions that could build on this work.My thesis describes the Greenpass client tools, which allow a guest to introduce himself to a delegator and allow the delegator to issue a new SPKI certificate to the guest. The guest does not need custom client software to introduce himself or to connect to the Wi-Fi network. The guest and delegator communicate using a set of Web applications. The guest obtains a temporary key pair and X.509 certificate if needed, then sends his public key value to a Web server we provide. The delegator looks up her guest\u27s public key and runs a Java applet that lets her verify her guests\u27 identity using visual hashing and issue a new SPKI certificate to him. The guest\u27s new certificate chain is stored as an HTTP cookie to enable him to push it to an authorization server at a later time. I also describe how Greenpass can be extended to control access to a virtual private network (VPN) and suggest several interesting future research and development directions that could build on this work

SECURING THE INTEGRITY OF THE POWER DISTRIBUTION SYSTEM FOR SMART GRID APPLICATIONS

The distribution system is one of the main components in a smart grid, readings are transferred from the distribution substations to the control center. Compromising transferred system data will result in drawing wrong conclusions about current operation status at the control center. Which leads to sending wrong operational commands that may result in very serious consequences. Firstly, we propose a scalable communications architecture for future smart grid distribution systems (i.e. Security Aware Distribution System Architecture - SADSA). The architecture is adaptable to use Wi-Fi or other technologies to transfer smart grid information. The architecture is studied from various angles. Both communication and cybersecurity challenges are extracted. In addition, the work provides a detailed discussion on how the proposed architecture meets National Institute of Standards and Technology (NIST) cybersecurity requirements for smart grids. Secondly, we propose the False Data Injection Prevention Protocol - FDIPP, the protocol prevents packet injection, duplication, alteration and node replication. In other words, it guarantees both system and data integrity. The protocol was analyzed using formal security analysis. Furthermore, Network Simulator 2 is used to evaluate both SADSA and FDIPP. The simulation is used to measure the delay and security overhead introduced from FDIPP and the proposed architectur

CONSTRUCTION OF EFFICIENT AUTHENTICATION SCHEMES USING TRAPDOOR HASH FUNCTIONS

In large-scale distributed systems, where adversarial attacks can have widespread impact, authentication provides protection from threats involving impersonation of entities and tampering of data. Practical solutions to authentication problems in distributed systems must meet specific constraints of the target system, and provide a reasonable balance between security and cost. The goal of this dissertation is to address the problem of building practical and efficient authentication mechanisms to secure distributed applications. This dissertation presents techniques to construct efficient digital signature schemes using trapdoor hash functions for various distributed applications. Trapdoor hash functions are collision-resistant hash functions associated with a secret trapdoor key that allows the key-holder to find collisions between hashes of different messages. The main contributions of this dissertation are as follows: 1. A common problem with conventional trapdoor hash functions is that revealing a collision producing message pair allows an entity to compute additional collisions without knowledge of the trapdoor key. To overcome this problem, we design an efficient trapdoor hash function that prevents all entities except the trapdoor key-holder from computing collisions regardless of whether collision producing message pairs are revealed by the key-holder. 2. We design a technique to construct efficient proxy signatures using trapdoor hash functions to authenticate and authorize agents acting on behalf of users in agent-based computing systems. Our technique provides agent authentication, assurance of agreement between delegator and agent, security without relying on secure communication channels and control over an agent’s capabilities. 3. We develop a trapdoor hash-based signature amortization technique for authenticating real-time, delay-sensitive streams. Our technique provides independent verifiability of blocks comprising a stream, minimizes sender-side and receiver-side delays, minimizes communication overhead, and avoids transmission of redundant information. 4. We demonstrate the practical efficacy of our trapdoor hash-based techniques for signature amortization and proxy signature construction by presenting discrete log-based instantiations of the generic techniques that are efficient to compute, and produce short signatures. Our detailed performance analyses demonstrate that the proposed schemes outperform existing schemes in computation cost and signature size. We also present proofs for security of the proposed discrete-log based instantiations against forgery attacks under the discrete-log assumption