Rainer Stütz, Peter Gaži, Bernhard Haslhofer, Jacob Illum
In the proof-of-stake (PoS) paradigm for maintaining decentralized, permissionless cryptocurrencies, Sybil attacks are prevented by basing the distribution of roles in the protocol execution on the stake distribution recorded in the ledger itself. However, for various reasons this distribution cannot be completely up-to-date, introducing a gap between the present stake distribution, which determines the parties' current incentives, and the one used by the protocol. In this paper, we investigate this issue, and empirically quantify its effects. We survey existing provably secure PoS proposals to observe that the above time gap between the two stake distributions, which we call stake distribution lag, amounts to several days for each of these protocols. Based on this, we investigate the ledgers of four major cryptocurrencies (Bitcoin, Bitcoin Cash, Litecoin and Zcash) and compute the average stake shift (the statistical distance of the two distributions) for each value of stake distribution lag between 1 and 14 days, as well as related statistics. We also empirically quantify the sublinear growth of stake shift with the length of the considered lag interval. Finally, we turn our attention to unusual stake-shift spikes in these currencies: we observe that hard forks trigger major stake shifts and that single real-world actors, mostly exchanges, account for major stake shifts in established cryptocurrency ecosystems.
Recently, application scenario of crowdsourcing IoT has covered to e-healthcare service, smart home, smart city, internet of vehicles due to the proliferation of smart devices such as smart mobile devices, smart wearable device, smart medical devices and smart furniture, etc. Patient's data collected by the smart devices send to the various remote medical servers. A group of medical professionals remote access patient data stored at the medical server database. Smart home users want to remote real-time access information of smart devices at home. All these operations need via wireless remote communication, which is suffering from various kinds of threat and attacks. Hence, there are a large number of multi-factor remote authentication and key agreement schemes designed for the application of crowdsourcing IoT. However, in most existing related multi-factor schemes, all factors for identity authentication only act as a parameter for encrypting the local secret key. In this paper, we propose a new secure remote multi-factor authentication scheme that includes three factors: 1) user identity; 2) password; and 3) user biometrics, which are authenticated by the remote server, act as a part of the secret key and participate in the key agreement process. We choose the chaotic map since it has a smaller key size and lower computational overhead, and then achieve remote multi-factor authentication and key agreement by artfully employ it to zero-knowledge technology and the fuzzy extractor technology. Our scheme is more secure and robust since the user revealing nothing sensitive information, and the adversary cannot impersonate any user even if he gets the server's master key. We have done security proof for our proposed scheme using the Random-Or-Real(ROR) model, Burrows-Abadi-Needham (BAN) logic, and ProVerif 2.00 to show that the presented scheme is secure. Also, we give an additional security analysis for other various attacks. Finally, according to the test and simulation result, the proposed scheme is very suitable for the power-constrained smart devices, and in the next generation 5G communication environment, its applicability and usability will be greatly enhanced.
Nowadays, with rapid advancements of vehicular telematics and communication techniques, proliferation of vehicular ad hoc networks (VANETs) have been witnessed, which facilitates the construction of promising intelligent transportation system (ITS). Due to inherent wireless communicating features in open environment, secure transmission among numerous VANET entities remains crucial issues. Currently, lots of research efforts have been made, while most of which tend to allocate the universal group key to the verified devices for both vehicle-to-vehicle (V2V) and vehicle-to-RSU (V2R) communications. However, in heterogeneous VANET environment with large numbers of devices in same vehicular group, complicated and variable topologies lead to continuous key updating in every moment, causing interference to regular V2R data exchange, which is not reliable and efficient for resource-constrained VANET environment. Moreover, group membership recording and detecting mechanisms are necessary for real time vehicle revocation and participation, which has not been further studied so far. In this paper, we address the above issues by proposing a secure authentication and key management scheme. In our design, novel VANET system model with edge computing infrastructure is adopted so as to offer adequate computing and storing capacity compared to traditional VANET structure. Note that our certificateless authentication scheme applies the independent session key for each vehicle for interference avoidance. Furthermore, consortium blockchain is employed for V2V group key construction. Real time group membership arrangement with efficient group key updating is accordingly provided. Formal security proofs are presented, demonstrating that the proposed scheme can achieve desired security properties. Performance analysis is conducted as well, proving that the proposed scheme is efficient compared with the state-of-the-arts.
We live in an era of information and it is very important to handle the exchange of information. While sending data to an authorized source, we need to protect it from unauthorized sources, changes, and authentication. ZKP technique can be used in designing secure authentication systems that dont involve any direct exchange of information between the claimant and the verifier thus preventing any possible leak of personal information. We propose a Zero-Knowledge Proof (ZKP) algorithm based on isomorphic graphs. We suggest most of the computations should be carried out on the users' web browser without revealing the password to the server at any point in time. Instead, it will generate random graphs and their permutations based on the login ID and password.
Les primitives lossy trapdoor, preuve à divulgation nulle de connaissance et applications Dans cette thèse, nous étudions deux primitives différentes : les lossy trapdoor functions (LTF) et les systèmes de preuve à divulgation nulle de connaissance. Les LTFs sont des familles de fonctions dans lesquelles les fonctions injectives et les fonctions lossy sont calculatoirement indistinguables. Depuis leur introduction, elles se sont avérées utiles pour la construction de diverses primitives cryptographiques. Nous donnons dans cette thèse des constructions efficaces d’une variante de la LTF : le filtre algébrique lossy. Avec cette variante, nous pouvons améliorer l’efficacité du schéma de chiffrement KDM-CCA et extracteur flous. Dans la deuxième partie de cette thèse, nous étudions les constructions de systèmes de preuve à divulgation nullle de connaissance. Nous donnons la première signature d’anneau de taille logarithmique avec la sécurité étroite en utilisant une variante de Groth-Kolhweiz Σ-protocole dans le modèle de l’oracle aléatoire. Nous proposons également une nouvelle construction d’arguments à divulgation nulle de connaissance non-intéractive et à vérifieur désigné (DVNIZK) sous l’hypothèse de réseaux Euclidiens. En utilisant cette nouvelle construction, nous construisons un système de vote basé sur les réseaux Euclidiens dans le modèle standard.
Srinivas Jangirala, Ashok Kumar Das, Athanasios V. Vasilakos
Secure real-time data about goods in transit in supply chains needs bandwidth having capacity that is not fulfilled with the current infrastructure. Hence, 5G-enabled Internet of Things (IoT) in mobile edge computing is intended to substantially increase this capacity. To deal with this issue, in this article, we design a new efficient lightweight blockchain-enabled radio frequency identification (RFID)-based authentication protocol for supply chains in 5G mobile edge computing environment, called lightweight blockchain-enabled RFID-based authentication protocol (LBRAPS). LBRAPS is based on bitwise exclusive-or (XOR), one-way cryptographic hash and bitwise rotation operations only. LBRAPS is shown to be secure against various attacks. Moreover, the simulation-based formal security verification using the broadly-accepted Automated Validation of Internet Security Protocols and Applications (AVISPA) tool assures that LBRAPS is secure. Finally, it is shown that LBRAPS has better trade-off among its security and functionality features, communication and computation costs as compared to those for existing protocols.
User authentication can rely on various factors (e.g., a password, a cryptographic key, biometric data) but should not reveal any secret or private information. This seemingly paradoxical feat can be achieved through zero-knowledge proofs. Unfortunately, naive password-based approaches still prevail on the web. Multi-factor authentication schemes address some of the weaknesses of the traditional login process, but generally have deployability issues or degrade usability even further as they assume users do not possess adequate hardware. This assumption no longer holds: smartphones with biometric sensors, cameras, short-range communication capabilities, and unlimited data plans have become ubiquitous. In this paper, we show that, assuming the user has such a device, both security and usability can be drastically improved using an augmented password-authenticated key agreement (PAKE) protocol and message authentication codes.
Bitcoin paper, published under a pseudonym Satoshi Nakamoto, opened a new era; cryptocurrencies, blockchain and distributed ledger technologies that are aiming distributed trust model. Even if there has been an ongoing extensive discussion both on the origin and the future about these developing technologies, number of products, studies and projects are increasing day by day. Among these the most crucial one is crypto wallets since the distributed trust and privacy preserving solutions are all relies on the underlying cryptographic primitives and the corresponding cryptographic keys. Almost all the cryptocurrencies require their users individually manage their own cryptographic keys or recommend use of cryptocurrency wallets. A cryptocurrency wallet or shortly, crypto wallet, has to generate and store one or more public-private keys and corresponding addresses. These keys authenticate corresponding transactions, hence any adversary who gains access to a wallet may seize all the assets secured with them. Therefore, cryptocurrency wallet solutions and products should be carefully analyzed and better to be certified if possible from the very beginning. \nIn this thesis, we mainly focus on to what extend and how a cryptocurrency wallet’s security analysis should be pursued. In order to formally portray the analysis framework, we propose to follow the Common Criteria (CC) Evaluation framework. CC evaluation framework is a formal evaluation methodology. For this purpose, assumptions, risks, threatsandsecurityvulnerabilitiesofthewalletswillbedefined. Also,objectivesshowing howthesethreatswillbecounteredinsidethewalletandwhatkindofmeasuresshouldbe taken by the environment and users will be detailed. In order to understand the security requirements, blockchain technology and Bitcoin which is the leading cryptocurrency will be explained and cryptocurrency wallets will be classified. In addition, we are going to propose a secure hardware wallet design in terms of physical and logical requirements. Then, we will compare the proposed wallet with other hardware wallets on the market. WebelievethatthisthesismaybebasicresourceforcreatingstandardizedCCdocuments such as Protection Profile(PP), Security Target(ST) etc. Furthermore, this study would be a brief source for cryptocurrency wallets’ design, test and analysis phases.
Blockchain has been emerging as a promising technology that could totally change the landscape of data security in the coming years, particularly for data access over Internet-of-Things and cloud servers. However, blockchain itself, though secured by its protocol, does not identify who owns the data and who uses the data. Other than simply encrypting data into keys, in this paper, we proposed a protocol called Biometric Blockchain (BBC) that explicitly incorporate the biometric cues of individuals to unambiguously identify the creators and users in a blockchain-based system, particularly to address the increasing needs to secure the food logistics, following the recently widely reported incident on wrongly labelled foods that caused the death of a customer on a flight. The advantage of using BBC in the food logistics is clear: it can not only identify if the data or labels are authentic, but also clearly record who is responsible for the secured data or labels. As a result, such a BBC-based solution can great ease the difficulty to control the risks accompanying the food logistics, such as faked foods or wrong gradient labels.
Myeonghyun Kim, Kisung Park, Sungjin Yu, Joonyoung Lee · 7 authors
Smart grids incorporating internet-of-things are emerging solutions to provide a reliable, sustainable and efficient electricity supply, and electric vehicle drivers can access efficient charging services in the smart grid. However, traditional electric vehicle charging systems are vulnerable to distributed denial of service and privileged insider attacks when the central charging server is attacked. The blockchain-based charging systems have been proposed to resolve these problems. In 2018, Huang et al. proposed the electric vehicle charging system using lightning network and smart contract. However, their system has an inefficient charging mechanism and does not guarantee security of key. We propose a secure charging system for electric vehicles based on blockchain to resolve these security flaws. Our charging system ensures the security of key, secure mutual authentication, anonymity, and perfect forward secrecy, and also provides efficient charging. We demonstrate that our proposed system provides secure mutual authentication using Burrows-Abadi-Needham logic and prevents replay and man-in-the-middle attacks using automated validation of internet security protocols and applications simulation tool. Furthermore, we compare computation and communication costs with previous schemes. Therefore, the proposed charging system efficiently applies to practical charging systems for electric vehicles.
Gustavo Betarte, Maximiliano Cristiá, Carlos Luna, Adrián Silveira · 5 authors
MimbleWimble is a privacy-oriented cryptocurrency technology encompassing security and scalability properties that distinguish it from other protocols of the kind. In this paper we present and briefly discuss those properties and outline the basis of a model-driven verification approach to address the certification of the correctness of a particular implementation of the protocol.
A phishing attack is one of the severe threats to the smartphone users. As per the recent lookout report, mobile phishing attack is increasing 85% year to year and going to become a significant threat to the smartphone users. This social engineering attack attempts to get the user’s password by disguising as trusted service provider. Most of the smartphone users are using the Internet services outside of the traditional firewall. Cloud-based documents are one of the primary targets of this phishing attack in mobile cloud computing. Also, most smartphone users are using the cloud storage in their device. To secure against this password attack in a mobile cloud environment, we propose a new authentication scheme to provide novel security to the mobile cloud services. This scheme will verify the user and service provider without transmitting the password using the Zero-knowledge proof based authentication protocol. Moreover, the proposed scheme will provide mutual authentication between the communication entities. The effectiveness of proposed scheme would be verified using protocol verification tool called Scyther.
Authentication is the act of confirming the validity of someone’s personal data. In the traditional authentication system, username and password are sent to the server for verification. However, this scheme is not secure, because the password can be sniffed. In addition, the server will keep the user’s password for the authentication. This makes the system vulnerable when the database server is hacked. Zero knowledge authentication allows server to authenticate user without knowing the user’s password. In this research, this scheme was implemented with Guillou-Quisquater protocol. Two login mechanisms were used: file-based certificate with key and local storage. Testing phase was carried out based on the Open Web Application Security Project (OWASP) penetration testing scheme. Furthermore, penetration testing was also performed by an expert based on Acunetix report. Three potential vulnerabilities were found and risk estimation was calculated. According to OWASP risk rating, these vulnerabilities were at the medium level.
Reto E. Koenig, Lukas Laederach, Cédric von Allmen
This paper describes a new but state-of-the-art approach to provide authenticity in mqtt sessions using the means of zero-knowledge-proofs. This approach completely voids session hijacking for the mqtt protocol and provides authenticity without the need for any network-security nor channel-security nor broker-based predefined ACLs. The presented approach does not require the broker to keep any secrets for session handling, what so ever. Moreover, it allows the clientID, which represents the identification for a session, to be publicly known. The presented approach allows completely anonymous but authentic sessions, hence the broker does not need any a priori knowledge of the client-party. As it is especially targeted for applications within the world of IoT, the presented approach is tuned to require only the minimum in extra power in terms of energy and space. The approach does not introduce any new concept, but simply fusions a state-of-the-art cryptographic zero knowledge proof of identity with the existing MQTT-5 specification. Thus no protocol extension is required in order to provide the targeted security properties. The described approach is completely agnostic to the application layer at the client side and is only required during mqtt-session establishment.
Vehicular Ad Hoc Networks (VANETs) are a particular subclass of mobile ad hoc networks that raise a number of security challenges, notably from the way users authenticate the network. Authentication technologies based on existing security policies and access control rules in such networks assume full trust on Roadside Unit (RSU) and authentication servers. The disclosure of authentication parameters enables user's trace-ability over the network. VANETs' trusted entities (e.g. RSU) can utilize such information to track a user traveling behavior, violating user privacy and anonymity. In this paper, we proposed a novel, light-weight, Adaptive Group-based Zero Knowledge Proof-Authentication Protocol (AGZKP-AP) for VANETs. The proposed authentication protocol is capable of offering various levels of users' privacy settings based on the type of services available on such networks. Our scheme is based on the Zero-Knowledge-Proof (ZKP) crypto approach with the support of trade-off options. Users have the option to make critical decisions on the level of privacy and the amount of resources usage they prefer such as short system response time versus the number of private information disclosures. Furthermore, AGZKP-AP is incorporated with a distributed privilege control and revoking mechanism that render user's private information to law enforcement in case of a traffic violation.
Due to the mobility of nodes, lack of infrastructure and limited computing and storage resources in mobile ad hoc networks (MANETs), this scheme uses the self-certification public key, combined with the interactive zero-knowledge proof and KEA+ key exchange method in the GPS identity authentication protocol, uses four interactions to complete the two-way identity authentication and key exchange of both parties, and which security is analyzed subsequently. The scheme effectively reduces the leakage of the claimant's secret knowledge in the identity authentication process, and enhances the reliability of the identity authentication and key exchange process.
Zero-knowledge password policy checks (ZKPPC) were introduced in Kiefer and Manulis’ report from 2014. The protocol aimed to solve the longstanding issue with servers requiring clients to provide their password in plain text to ensure its strength. Their protocol was intended to eliminate the need for users to trust the server to store and handle passwords correctly while simultaneously allowing the server to know that the registered password was strong enough. This thesis has investigated the soundness of the protocol by Kiefer and Manulis and will present three new zero-day vulnerabilities discovered in the process. The vulnerabilities allow a dishonest user to prove adherence to the policy for invalid passwords. Additionally, the thesis presents our new Proof of Inequality which prevents one of these vulnerabilities, as well as an extension for an incomplete part of the protocol. The two remaining zero-day vulnerabilities are weaknesses in the protocol left for future research.
Identity-based mutual authentication and key agreement (ID-MAKA) between a mobile user and cloud service provider is necessary for accessing any cloud services. In recent years, there are a large number of ID-MAKA schemes had been proposed on mobile cloud computing services to make authentication and accessing process more usability, security, and scalability. In this paper, we propose a new ID-MAKA scheme for mobile cloud computing, which firstly achieves remote biometric-based authentication(remote servers authenticate user's biometrics), single sign-on (a single credential and single registration for accessing multiple servers) and center-less authentication(the registration center does not participate in the access procedure) in one scheme. In order to realize this target, we design a ZK-token based on ECC and cryptographic hash function, and then artfully employ it to introduce the fuzzy extractor technology and zero-knowledge technology into our scheme. Therefore, the user can access multiple cloud computing servers by registering only once in the registration center, and cloud computing servers can complete the biometric-based remote authentication and key agreement for the user without the registration center participating. In this way, our scheme greatly improves usability, scalability, and security compared to other existing solutions. We give a formal security proof for our scheme by using Real-Or-Random(RoR) model and Burrows-Abadi-Needham (BAN) logic to show that the present scheme is secure and security analysis for other known attacks. Finally, according to the experiment result, our scheme has lower computation and communication cost compared with most existing related schemes.
In order to deploy a secure WLAN mesh network, authentication of both users and APs is needed, and a secure authentication mechanism should be employed. However, some additional configurations of trusted third party agencies are still needed on-site to deploy a secure authentication system. This paper proposes a new block chain-based authentication protocol for WLAN mesh security access, to reduce the deployment costs and resolve the issues of requiring key delivery and central server during IEEE 802.11X authentication. This method takes the user’s authentication request as a transaction, considers all the authentication records in the mesh network as the public ledger and realizes the effective monitoring of the malicious attack. Finally, this paper analyzes the security of the protocol in detail, and proves that the new method can solve the dependence of the authentication node on PKI and CA.
We propose a cryptographic protocol with zero-knowledge proof (ZKP) on elliptic curves (EC) using public keys and random messages, allowing to establish the truth of a statement not conveying any additional information about the statement itself. The cryptographic protocols based on zero-knowledge proof allow identification, key exchange and other cryptographic operations to be performed without leakage of sensitive information during the information exchange. The implementation of the cryptographic protocol of the zero-knowledge proof on the basis of the mathematical apparatus of elliptic curves allows to significantly reduce the size of the protocol parameters and increase its cryptographic strength (computational complexity of the breaking). The security of cryptosystems involving elliptic curves is based on the difficulty of solving the elliptic curve discrete logarithm problem. We determine the completeness and correctness of the protocol and give an example of the calculation is given. The cryptographic protocol was modeled in the High-Level Protocol Specification Language, the model validation and verification of the protocol were also performed. The software verification of the cryptographic protocol was performed using the software modules On the Fly Model Checker and Constraint Logic based Attack Searcher. In order to validate the cryptographic protocol resistance to intruder attacks, we used the Security Protocol Animator package for Automated Validation of Internet Security Protocols and Applications. The security of the proposed cryptographic protocol ZKP EC is based on the difficulty of solving the elliptic curve discrete logarithm problem). The recommended elliptical curves according to DSTU 4145-2002 may be used to implement such cryptographic protocol.