Advances in cryptographic voting systems

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.Includes bibliographical references (p. 241-254).Democracy depends on the proper administration of popular elections. Voters should receive assurance that their intent was correctly captured and that all eligible votes were correctly tallied. The election system as a whole should ensure that voter coercion is unlikely, even when voters are willing to be influenced. These conflicting requirements present a significant challenge: how can voters receive enough assurance to trust the election result, but not so much that they can prove to a potential coercer how they voted? This dissertation explores cryptographic techniques for implementing verifiable, secret-ballot elections. We present the power of cryptographic voting, in particular its ability to successfully achieve both verifiability and ballot secrecy, a combination that cannot be achieved by other means. We review a large portion of the literature on cryptographic voting. We propose three novel technical ideas: 1. a simple and inexpensive paper-base cryptographic voting system with some interesting advantages over existing techniques, 2. a theoretical model of incoercibility for human voters with their inherent limited computational ability, and a new ballot casting system that fits the new definition, and 3. a new theoretical construct for shuffling encrypted votes in full view of public observers.by Ben Adida.Ph.D

SPKI/SDSI HTTP Server / Certificate Chain Discovery in SPKI/SDSI

Thesis (M.Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.Includes bibliographical references (leaves 155-160).The issue of trust is of growing importance as our communities become increasingly interconnected. When resources are shared over an untrusted network, how are decisions on which principals are authorized to perform particular actions determined? SPKI/SDSI, a security infrastructure based on public-keys, is designed to facilitate the development of scalable, secure, distributed computing systems. It provides fine-grained access control, using a local name space hierarchy, and a simple, flexible, trust policy model; these features allow for the ability to create groups and delegate authorizations. Project Geronimo, named after the famous Native-American Apache chief, explores the viability of SPKI/SDSI by using it to provide access control over the Web. The infrastructure was integrated into the Netscape web client and Apache web server, using a previously developed SPKI/SDSI C Library. This thesis focuses on the server implementation. An SPKI/SDSI Apache module was designed and implemented: its principle functions are to protect web objects using SPKI/SDSI ACLs, and to determine whether HTTP client requests should be permitted to perform particular operations on protected objects. An administrative tool was developed to enable ACLs to be created, and updated, securely. The thesis also describes the algorithm for certificate chain discovery in SPKI/SDSI. Finally, the demonstration developed for Project Geronimo is outlined. The demo was successfully shown to our sponsors and various groups within the Laboratory for Computer Science.by Dwaine E. Clarke.M.Eng

Wireless LAN security.

Chan Pak To Patrick.Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.Includes bibliographical references (leaves 82-86).Abstracts in English and Chinese.Abstract --- p.iAcknowledgement --- p.iiiContents --- p.ivList of Figures --- p.viiList of Tables --- p.viiiChapter 1 --- Introduction --- p.1Chapter 1.1 --- Motivation --- p.1Chapter 1.2 --- The Problems --- p.3Chapter 1.3 --- My Contribution --- p.4Chapter 1.4 --- Thesis Organization --- p.5Chapter 2 --- Wireless LAN Security Model --- p.6Chapter 2.1 --- Preliminary Definitions on WLAN --- p.6Chapter 2.2 --- Security Model --- p.7Chapter 2.2.1 --- Security Attributes --- p.7Chapter 2.2.2 --- Security Threats in WLAN --- p.8Chapter 2.2.3 --- Attacks on Authentication Scheme --- p.10Chapter 2.2.4 --- Attacks on Keys --- p.10Chapter 2.3 --- Desired Properties of WLAN Authentication --- p.11Chapter 2.3.1 --- Security Requirements of WLAN Authentication --- p.11Chapter 2.3.2 --- Security Requirements of Session Keys --- p.12Chapter 2.3.3 --- Other Desired Properties of WLAN Authentication --- p.12Chapter 3 --- Cryptography --- p.14Chapter 3.1 --- Overview on Cryptography --- p.14Chapter 3.2 --- Symmetric-key Encryption --- p.15Chapter 3.2.1 --- Data Encryption Standard (DES) --- p.15Chapter 3.2.2 --- Advanced Encryption Standard (AES) --- p.15Chapter 3.2.3 --- RC4 --- p.16Chapter 3.3 --- Public-key Cryptography --- p.16Chapter 3.3.1 --- RSA Problem and Related Encryption Schemes --- p.17Chapter 3.3.2 --- Discrete Logarithm Problem and Related Encryption Schemes --- p.18Chapter 3.3.3 --- Elliptic Curve Cryptosystems --- p.19Chapter 3.3.4 --- Digital Signature --- p.19Chapter 3.4 --- Public Key Infrastructure --- p.20Chapter 3.5 --- Hash Functions and Message Authentication Code --- p.21Chapter 3.5.1 --- SHA-256 --- p.22Chapter 3.5.2 --- Message Authentication Code --- p.22Chapter 3.6 --- Entity Authentication --- p.23Chapter 3.6.1 --- ISO/IEC 9798-4 Three-pass Mutual --- p.23Chapter 3.6.2 --- ISO/IEC 9798-4 One-pass Unilateral --- p.24Chapter 3.7 --- Key Establishment --- p.24Chapter 3.7.1 --- Diffie-Hellman Key Exchange --- p.24Chapter 3.7.2 --- Station-to-Station Protocol --- p.25Chapter 3.8 --- Identity-Based Cryptography --- p.25Chapter 3.8.1 --- The Boneh-Franklin Encryption Scheme --- p.26Chapter 3.8.2 --- Au and Wei's Identification Scheme and Signature Scheme --- p.27Chapter 4 --- Basics of WLAN Security and WEP --- p.29Chapter 4.1 --- Basics of WLAN Security --- p.29Chapter 4.1.1 --- "Overview on ""Old"" WLAN Security" --- p.29Chapter 4.1.2 --- Some Basic Security Measures --- p.29Chapter 4.1.3 --- Virtual Private Network (VPN) --- p.30Chapter 4.2 --- WEP --- p.31Chapter 4.2.1 --- Overview on Wired Equivalent Privacy (WEP) --- p.31Chapter 4.2.2 --- Security Analysis on WEP --- p.33Chapter 5 --- IEEE 802.11i --- p.38Chapter 5.1 --- Overview on IEEE 802.11i and RSN --- p.38Chapter 5.2 --- IEEE 802.1X Access Control in IEEE 802.11i --- p.39Chapter 5.2.1 --- Participants --- p.39Chapter 5.2.2 --- Port-based Access Control --- p.40Chapter 5.2.3 --- EAP and EAPOL --- p.40Chapter 5.2.4 --- RADIUS --- p.41Chapter 5.2.5 --- Authentication Message Exchange --- p.41Chapter 5.2.6 --- Security Analysis --- p.41Chapter 5.3 --- RSN Key Management --- p.43Chapter 5.3.1 --- RSN Pairwise Key Hierarchy --- p.43Chapter 5.3.2 --- RSN Group Key Hierarchy --- p.43Chapter 5.3.3 --- Four-way Handshake and Group Key Handshake --- p.44Chapter 5.4 --- RSN Encryption and Data Integrity --- p.45Chapter 5.4.1 --- TKIP --- p.45Chapter 5.4.2 --- CCMP --- p.46Chapter 5.5 --- Upper Layer Authentication Protocols --- p.47Chapter 5.5.1 --- Overview on the Upper Layer Authentication --- p.47Chapter 5.5.2 --- EAP-TLS --- p.48Chapter 5.5.3 --- Other Popular ULA Protocols --- p.50Chapter 6 --- Proposed IEEE 802.11i Authentication Scheme --- p.52Chapter 6.1 --- Proposed Protocol --- p.52Chapter 6.1.1 --- Overview --- p.52Chapter 6.1.2 --- The AUTHENTICATE Protocol --- p.56Chapter 6.1.3 --- The RECONNECT Protocol --- p.59Chapter 6.1.4 --- Packet Format --- p.61Chapter 6.1.5 --- Ciphersuites Negotiation --- p.64Chapter 6.1.6 --- Delegation --- p.64Chapter 6.1.7 --- Identity Privacy --- p.68Chapter 6.2 --- Security Considerations --- p.68Chapter 6.2.1 --- Security of the AUTHENTICATE protocol --- p.68Chapter 6.2.2 --- Security of the RECONNECT protocol --- p.69Chapter 6.2.3 --- Security of Key Derivation --- p.70Chapter 6.2.4 --- EAP Security Claims and EAP Methods Requirements --- p.72Chapter 6.3 --- Efficiency Analysis --- p.76Chapter 6.3.1 --- Overview --- p.76Chapter 6.3.2 --- Bandwidth Performance --- p.76Chapter 6.3.3 --- Computation Speed --- p.76Chapter 7 --- Conclusion --- p.79Chapter 7.1 --- Summary --- p.79Chapter 7.2 --- Future Work --- p.80Bibliography --- p.8

Authentication for mobile computing

Host mobility is becoming an increasingly important feature with the recent arrival of laptop and palmtop computers, the development of wireless network interfaces and the implementation of global networks. Unfortunately, this mobile environment is also much more vulnerable to penetration by intruders. A possible means of protection can be authentication. This guarantees the identity of a communication peer. This thesis studies the constraints imposed on the mobile environment with respect to authentication. It compares the two prevailing authentication mechanisms, Kerberos and SPX, and tries to make suggestions of how a mechanism can be adapted to the mobile environment

A Lightweight Multifactor Authentication Scheme for Wireless Sensor Networks in the Internet of Things

Internet of Things (IoT) has become an information bridge between societies. Wireless sensor networks (WSNs) are one of the emergent technologies that work as themain force in IoT. Applications based on WSN includeenvironment monitoring, smart healthcare, user legitimacy authentication, and data security. Recently, many multifactoruser authentication schemes for WSNs have been proposedusing smart cards, passwords, as well as biometric features. Unfortunately, these schemes are shown to be susceptibletowards several attacks and these includes password guessing attack, impersonation attack, and Man-in-the-middle (MITM) attack due to non-uniform security evaluation criteria. In this paper, we propose a lightweight multifactor authentication scheme using only hash function of the timestamp (TS) and One Time Password (OTP). Furthermore, public key and private key is incorporated to secure the communication channel. The security analysis shows that the proposed scheme satisfies all the security requirement and insusceptible towards some wellknown attack (password guessing attack, impersonation attack and MITM)

FLBP: A Federated Learning-enabled and Blockchain-supported Privacy-Preserving of Electronic Patient Records for the Internet of Medical Things

The evolution of the computing paradigms and the Internet of Medical Things (IoMT) have transfigured the healthcare sector with an alarming rise of privacy issues in healthcare records. The rapid growth of medical data leads to privacy and security concerns to protect the confidentiality and integrity of the data in the feature-loaded infrastructure and applications. Moreover, the sharing of medical records of a patient among hospitals rises security and interoperability issues. This article, therefore, proposes a Federated Learning-and-Blockchain-enabled framework to protect electronic medical records from unauthorized access using a deep learning technique called Artificial Neural Network (ANN) for a collaborative IoMT-Fog-Cloud environment. ANN is used to identify insiders and intruders. An Elliptical Curve Digital Signature (ECDS) algorithm is adopted to devise a secured Blockchain-based validation method. To process the anti-malicious propagation method, a Blockchain-based Health Record Sharing (BHRS) is implemented. In addition, an FL approach is integrated into Blockchain for scalable applications to form a global model without the need of sharing and storing the raw data in the Cloud. The proposed model is evident from the simulations that it improves the operational cost and communication (latency) overhead with a percentage of 85.2% and 62.76%, respectively. The results showcase the utility and efficacy of the proposed model

Security mechanisms for next-generation mobile networks

Basic concepts and definitions -- Motivation and research challenges -- Research objectives -- Mobile value-added service access -- UMTS access security -- DoS attacks in mobile networks -- A lightweight mobile service access based on reusable tickets -- Background work and motivation -- Service access through tickets -- System security analysis -- Comparisons with related work -- Enhancing UMTS AKA with vector combination -- Overview of UMTS AKA -- UMTS AKA weaknesses- -- Vector combination based AKA -- Security analysis of VC-AKA -- Mobility-oriented AKA in UMTS -- Mobility-oriented authentication -- Security analysis of MO-AKA -- A fine-grained puzzle against DOS attacks -- Quasi partial collision -- Fine-grained control over difficulties -- Lightweight to mobile devices -- Against replay attacks -- Confidentiality, integrity and user privacy

Universal semantic communication

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 325-334).Is meaningful communication possible between two intelligent parties who share no common language or background? We propose that this problem can be rigorously addressed by explicitly focusing on the goals of the communication. We propose a theoretical framework in which we can address when and to what extent such semantic communication is possible. Our starting point is a mathematical definition of a generic goal for communication, that is pursued by agents of bounded computational complexity. We then model a "lack of common language or background" by considering a class of potential partners for communication; in general, this formalism is rich enough to handle varying degrees of common language and backgrounds, but the complete lack of knowledge is modeled by simply considering the class of all partners with which some agent of similar power could achieve our goal. In this formalism, we will find that for many goals (but not all), communication without any common language or background is possible. We call the strategies for achieving goals without relying on such background universal protocols. The main intermediate notions introduced by our theory are formal notions of feedback that we call sensing. We show that sensing captures the essence of whether or not reliable universal protocols can be constructed in many natural settings of interest: we find that across settings, sensing is almost always sufficient, usually necessary, and generally a useful design principle for the construction of universal protocols. We support this last point by developing a number of examples of protocols for specific goals. Notably, we show that universal delegation of computation from a space-efficient client to a general-purpose server is possible, and we show how a variant of TCP can allow end-users on a packet network to automatically adapt to small changes in the packet format (e.g., changes in IP). The latter example above alludes to our main motivation for considering such problems, which is to develop techniques for modeling and constructing computer systems that do not require that their components strictly adhere to protocols: said differently, we hope to be able to design components that function properly with a sufficiently wide range of other components to permit a rich space of "backwards-compatible" designs for those components. We expect that in the long run, this paradigm will lead to simpler systems because "backwards compatibility" is no longer such a severe constraint, and we expect it to lead to more robust systems, partially because the components should be simpler, and partially because such components are inherently robust to deviations from any fixed protocol. Unfortunately, we find that the techniques for communication under the complete absence of any common background suffer from overhead that is too severe for such practical purposes, so we consider two natural approaches for introducing some assumed common background between components while retaining some nontrivial amount of flexibility. The first approach supposes that the designer of a component has some "belief" about what protocols would be "natural" to use to interact with other components; we show that, given sensing and some sufficient "agreement" between the beliefs of the designers of two components, the components can be made universal with some relatively modest overhead. The second approach supposes that the protocols are taken from some restricted class of functions, and we will see that for certain classes of functions and simple goals, efficient universal protocols can again be constructed from sensing. Actually, we show more: the special case of our model described in the second approach above corresponds precisely to the well-known model of mistake-bounded on-line learning first studied by Barzdirs and Frievalds, and later considered in more depth by Littlestone. This connection provides a reasonably complete picture of the conditions under which we can apply the second approach. Furthermore, it also seems that the first approach is closely related to the problem of designing good user interfaces in Human-Computer Interaction. We conclude by briefly sketching the connection, and suggest that further development of this connection may be a potentially fruitful direction for future work.by Brendan Juba.Ph.D

Secure socket layer protocol simulation in Java

This project aims to study the performance of Secure Sockets Layer (SSL) Protocol implemented in JAVA for web applications. Secure Sockets Layer protocol allows client/server applications to communicate in a way that is designed to prevent eavesdropping, tampering, or message forgery. In particular, this project focuses on an implementation of the SSL protocol used for secure data exchange between a web server (Server) and a browser (Client) through socket programming. This Secure Sockets Layer Protocol in JAVA can be executed on any machine having JAVA Virtual Machine (VM) installed. In this project, the SSL protocol was designed to authenticate the server, and optionally the client by creating software keys on both the sides in JAVA. The authentication process uses Public-Key Encryption and Digital Signatures to verify the identity of the server. Once the server has been authenticated, the client and server use techniques of Symmetric-Key Encryption, which is very fast, to encrypt all the information they exchange for the remainder of the session and to detect any tampering that may have occurred. In this project, the maximum file size that can be encrypted and then transferred from the server to the client is 10 Megabytes

A Blockchain Application Prototype for the Internet of Things

The emergence of the Internet of things (IoT), associated with the explosion in the number of connected objects, and the growth in user needs, makes the Internet network very complex. IoT objects are diverse and heterogeneous, which requires establishing interoperability and efficient identity management on the one hand. On the other hand, centralized architectures such as cloud-based ones can have overhead and high latency, with a potential risk of failure. Facing these challenges, Blockchain technology, with its decentralized architecture based on a distributed peer-to-peer network, offers a new infrastructure that allows IoT objects to interact reliably and securely. In this paper, a new approach is proposed with a three-layer architecture: layer of sensing and collection of data made up of the IoT network, layer of processing and saving of data exchanges at the Blockchain level, and access and visualization layer via a web interface. The prototype implemented in this study allows all transactions (data exchanges) generated by IoT devices to be recorded and stored on a dedicated Blockchain, assuring the security of IoT objects\u27 communications. This prototype also enables access to and visualization of all data and information, thus enhancing the IoT network\u27s transparency