5,790 research outputs found
Foundations, Properties, and Security Applications of Puzzles: A Survey
Cryptographic algorithms have been used not only to create robust ciphertexts
but also to generate cryptograms that, contrary to the classic goal of
cryptography, are meant to be broken. These cryptograms, generally called
puzzles, require the use of a certain amount of resources to be solved, hence
introducing a cost that is often regarded as a time delay---though it could
involve other metrics as well, such as bandwidth. These powerful features have
made puzzles the core of many security protocols, acquiring increasing
importance in the IT security landscape. The concept of a puzzle has
subsequently been extended to other types of schemes that do not use
cryptographic functions, such as CAPTCHAs, which are used to discriminate
humans from machines. Overall, puzzles have experienced a renewed interest with
the advent of Bitcoin, which uses a CPU-intensive puzzle as proof of work. In
this paper, we provide a comprehensive study of the most important puzzle
construction schemes available in the literature, categorizing them according
to several attributes, such as resource type, verification type, and
applications. We have redefined the term puzzle by collecting and integrating
the scattered notions used in different works, to cover all the existing
applications. Moreover, we provide an overview of the possible applications,
identifying key requirements and different design approaches. Finally, we
highlight the features and limitations of each approach, providing a useful
guide for the future development of new puzzle schemes.Comment: This article has been accepted for publication in ACM Computing
Survey
Quantum-secured blockchain
Blockchain is a distributed database which is cryptographically protected
against malicious modifications. While promising for a wide range of
applications, current blockchain platforms rely on digital signatures, which
are vulnerable to attacks by means of quantum computers. The same, albeit to a
lesser extent, applies to cryptographic hash functions that are used in
preparing new blocks, so parties with access to quantum computation would have
unfair advantage in procuring mining rewards. Here we propose a possible
solution to the quantum era blockchain challenge and report an experimental
realization of a quantum-safe blockchain platform that utilizes quantum key
distribution across an urban fiber network for information-theoretically secure
authentication. These results address important questions about realizability
and scalability of quantum-safe blockchains for commercial and governmental
applications.Comment: 7 pages, 2 figures; published versio
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A two‐step authentication framework for Mobile ad hoc networks
The lack of fixed infrastructure in ad hoc networks causes nodes to rely more heavily on peer nodes for communication. Nevertheless, establishing trust in such a distributed environment is very difficult, since it is not straightforward for a node to determine if its peer nodes can be trusted. An additional concern in such an environment is with whether a peer node is merely relaying a message or if it is the originator of the message. In this paper, we propose an authentication approach for protecting nodes in mobile ad hoc networks. The security requirements for protecting data link and network layers are identified and the design criteria for creating secure ad hoc networks using several authentication protocols are analyzed. Protocols based on zero knowledge and challenge response techniques are presented and their performance is evaluated through analysis and simulation
Security and Privacy Issues in Wireless Mesh Networks: A Survey
This book chapter identifies various security threats in wireless mesh
network (WMN). Keeping in mind the critical requirement of security and user
privacy in WMNs, this chapter provides a comprehensive overview of various
possible attacks on different layers of the communication protocol stack for
WMNs and their corresponding defense mechanisms. First, it identifies the
security vulnerabilities in the physical, link, network, transport, application
layers. Furthermore, various possible attacks on the key management protocols,
user authentication and access control protocols, and user privacy preservation
protocols are presented. After enumerating various possible attacks, the
chapter provides a detailed discussion on various existing security mechanisms
and protocols to defend against and wherever possible prevent the possible
attacks. Comparative analyses are also presented on the security schemes with
regards to the cryptographic schemes used, key management strategies deployed,
use of any trusted third party, computation and communication overhead involved
etc. The chapter then presents a brief discussion on various trust management
approaches for WMNs since trust and reputation-based schemes are increasingly
becoming popular for enforcing security in wireless networks. A number of open
problems in security and privacy issues for WMNs are subsequently discussed
before the chapter is finally concluded.Comment: 62 pages, 12 figures, 6 tables. This chapter is an extension of the
author's previous submission in arXiv submission: arXiv:1102.1226. There are
some text overlaps with the previous submissio
Efficient and Low-Cost RFID Authentication Schemes
Security in passive resource-constrained Radio Frequency Identification
(RFID) tags is of much interest nowadays. Resistance against illegal tracking,
cloning, timing, and replay attacks are necessary for a secure RFID
authentication scheme. Reader authentication is also necessary to thwart any
illegal attempt to read the tags. With an objective to design a secure and
low-cost RFID authentication protocol, Gene Tsudik proposed a timestamp-based
protocol using symmetric keys, named YA-TRAP*. Although YA-TRAP* achieves its
target security properties, it is susceptible to timing attacks, where the
timestamp to be sent by the reader to the tag can be freely selected by an
adversary. Moreover, in YA-TRAP*, reader authentication is not provided, and a
tag can become inoperative after exceeding its pre-stored threshold timestamp
value. In this paper, we propose two mutual RFID authentication protocols that
aim to improve YA-TRAP* by preventing timing attack, and by providing reader
authentication. Also, a tag is allowed to refresh its pre-stored threshold
value in our protocols, so that it does not become inoperative after exceeding
the threshold. Our protocols also achieve other security properties like
forward security, resistance against cloning, replay, and tracking attacks.
Moreover, the computation and communication costs are kept as low as possible
for the tags. It is important to keep the communication cost as low as possible
when many tags are authenticated in batch-mode. By introducing aggregate
function for the reader-to-server communication, the communication cost is
reduced. We also discuss different possible applications of our protocols. Our
protocols thus capture more security properties and more efficiency than
YA-TRAP*. Finally, we show that our protocols can be implemented using the
current standard low-cost RFID infrastructures.Comment: 21 pages, Journal of Wireless Mobile Networks, Ubiquitous Computing,
and Dependable Applications (JoWUA), Vol 2, No 3, pp. 4-25, 201
Shake well before use: Authentication based on Accelerometer Data
Small, mobile devices without user interfaces, such as Bluetooth headsets, often need to communicate securely over wireless networks. Active attacks can only be prevented by authenticating wireless communication, which is problematic when devices do not have any a priori information about each other. We introduce a new method for device-to-device authentication by shaking devices together. This paper describes two protocols for combining cryptographic authentication techniques with known methods of accelerometer data analysis to the effect of generating authenticated, secret keys. The protocols differ in their design, one being more conservative from a security point of view, while the other allows more dynamic interactions. Three experiments are used to optimize and validate our proposed authentication method
Secure and Privacy-Preserving Data Aggregation Protocols for Wireless Sensor Networks
This chapter discusses the need of security and privacy protection mechanisms
in aggregation protocols used in wireless sensor networks (WSN). It presents a
comprehensive state of the art discussion on the various privacy protection
mechanisms used in WSNs and particularly focuses on the CPDA protocols proposed
by He et al. (INFOCOM 2007). It identifies a security vulnerability in the CPDA
protocol and proposes a mechanism to plug that vulnerability. To demonstrate
the need of security in aggregation process, the chapter further presents
various threats in WSN aggregation mechanisms. A large number of existing
protocols for secure aggregation in WSN are discussed briefly and a protocol is
proposed for secure aggregation which can detect false data injected by
malicious nodes in a WSN. The performance of the protocol is also presented.
The chapter concludes while highlighting some future directions of research in
secure data aggregation in WSNs.Comment: 32 pages, 7 figures, 3 table
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