Blockchain Papers

Thomas Haines, Johannes Müller

No abstract is available for this record.

Xavier Salleras, Vanesa Daza

Zero-Knowledge Proofs (ZKPs) are cryptographic primitives allowing a party to prove to another party that the former knows some information while keeping it secret. Such a premise can lead to the development of numerous privacy-preserving protocols in different scenarios, like proving knowledge of some credentials to a server without leaking the identity of the user. Even when the applications of ZKPs were endless, they were not exploited in the wild for a couple of decades due to the fact that computing and verifying proofs was too computationally expensive. However, the advent of efficient schemes (in particular, zk-SNARKs) made this primitive to break into the scene in fields like cryptocurrencies, smart-contracts, and more recently, self-sovereign scenarios: private-by-design identity management and authentication. Nevertheless, its adoption in environments like the Internet of Things (IoT) remains unexplored due to the computational limitations of embedded systems. In this paper, we introduce ZPiE, a C library intended to create ZKP applications to be executed in embedded systems. Its main feature is portability: it can be compiled, executed, and used out-of-the-box in a wide variety of devices. Moreover, our proof-of-concept has been proved to work smoothly in different devices with limited resources, which can execute state-of-the-art ZKP authentication protocols.

Altynbek Seitenov, Gulnur Smagulova

Abstract: In the contemporary world, Ethereum is a very reliable financial saving among cryptocurrencies. It is also well known as a blockchain platform for creating and launching its own cryptocurrency. The applications run on Ethereum executed by a platform-specific cryptographic token, ether. During 2014, Ethereum had launched a pre-sale for ether, which had received an overwhelming response. Ether is used broadly for two purposes: it is traded as a digital currency exchange like other cryptocurrencies, and it is used inside Ethereum to run applications and even to monetize work. It should be noticed that the smart contract has brought a significant share of the success to Ethereum. The smart contract is a computer programme that independently performs assigned tasks between network participants without the participation of a third trusted party. Smart contracts and their intranet transactions have facilitated the rapid expansion of the Ethereum network. Smart contracts are widely represented on the market, either as electronic transaction payments or as applications for the implementation of logistics supplies, gambling, and other sectors. These transactions are irreversible and fully tracked online. Whereas the electronic records are available in a public distributed ledger and include data about user addresses, whereas the real names are hidden. The article explains the usage of decentralized accounts and their electronic transactions in the Ethereum network. The results are presented through different application sectors. Additionally, a new method for extracting blockchain records through node cluster via IPFS path is implemented in the research.

Andrea Tesei, Domenico Lattuca, Marco Luise, Paolo Pagano · 6 authors

The widespread adoption of Cooperative, Connected, and Automated Mobility (CCAM) applications requires the implementation of stringent security mechanisms to minimize the surface of cyber attacks. Authentication is an effective process for validating user identity in vehicular networks. However, authentication alone is not enough to prevent dangerous attack situations. Existing security mechanisms are not able to promptly revoke the credentials of misbehaving vehicles, thus tolerate malicious actors to remain trusted in the system for a long time. The resulting vulnerability window allows the implementation of complex attacks, thus posing a substantial impairment to the security of the vehicular ecosystem. In this paper we propose a Distributed Ledger-based Vehicular Revocation Scheme that improves the state of the art by providing a \textit{vulnerability window} lower than 1 second, reducing well-behaved vehicles exposure to sophisticated and potentially dangerous attacks. The proposed scheme harnesses the advantages of the underlying Distributed Ledger Technology (DLT) to implement a privacy-aware revocation process while being fully transparent to all participating entities. Furthermore, it meets the critical message processing times defined by EU and US standards, thus closing a critical gap in the current international standards. Theoretical analysis and experimental validation demonstrate the effectiveness and efficiency of the proposed scheme, where DLT streamlines the revocation operation overhead and delivers an economically viable yet scalable solution against cyber attacks on vehicular systems.

Maliha Sultana, Afrida Hossain, Fabiha Laila, Kazi Abu Taher · 5 authors

BACKGROUND: Data security has been a critical topic of research and discussion since the onset of data sharing in e-health systems. Although digitalization of data has increased efficiency and speed, it has also made data vulnerable to cyber attacks. Medical records in particular seem to be the regular victims of hackers. Several data breach incidents throughout history have warranted the invention of security measures against these threats. Although various security procedures like firewalls, virtual private networks, encryption, etc are present, a mix of these approaches are required for maximum security in medical image and data sharing. METHODS: Relatively new, blockchain has become an effective tool for safeguarding sensitive information. However, to ensure overall protection of medical data (images), security measures have to be taken at each step, from the beginning, during and even after transmission of medical images which is ensured by zero trust security model. In this research, a number of studies that deal with these two concepts were studied and a decentralized and trustless framework was proposed by combining these two concepts for secured medical data and image transfer and storage. RESULTS: Research output suggested blockchain technology ensures data integrity by maintaining an audit trail of every transaction while zero trust principles make sure the medical data is encrypted and only authenticated users and devices interact with the network. Thus the proposed model solves a lot of vulnerabilities related to data security. CONCLUSIONS: A system to combat medical/health data vulnerabilities has been proposed. The system makes use of the immutability of blockchain, the additional security of zero trust principles, and the scalability of off chain data storage using Inter Planetary File Systems (IPFS). The adoption of this system suggests to enhance the security of medical or health data transmission.

Guangsong Li, Yang Wang, Bin Zhang, Siqi Lu

Nowadays, it is still a major challenge to design a secure cross-domain authentication protocol for heterogeneous wireless networks with different security parameters. As a new technology, blockchain has attracted people’s attention because of its tamper-proof and decentralized characteristics. In this paper, we propose a cross-domain authentication and key agreement system based on smart contract of blockchains. Public keys of the nodes are managed using the smart contracts, and the system parameters are confirmed by contract query. On this basis, a cross-domain authentication and key agreement protocol is designed. In this protocol, roaming users can select temporary authentication parameters according to the system parameters of the roaming domain to complete authentication and key agreement, and users are anonymous in the process. Security of the protocol is demonstrated under the CK model, and two formal analysis tools are used to further analyze the protocol. Since the protocol does not have complex cryptographic operations and certificate verification, it has lower computational and communication overhead.

V. Lakshman Narayana, Divya Midhunchakkaravarthy

Mobile Ad hoc Networks (MANETs) are non-fixed framework systems and there are such a large number of issues with them because of their dynamic topology, portable nodes, security, data transfer capacity, restricted battery strength and so forth. Trust is an association, dependability, unwavering excellence, and loyalty of the nodes in the system. A trusted routing plan is essential to guarantee the routing security and productivity of sensor systems. In perspective on these issues, this manuscript proposes a trusted routing plan utilizing block chain and building up a security model to improve the routing security and productivity for ad hoc networks. The possible routing plan is given for acquiring routing data of routing nodes on the block chain, which makes the routing data distinct and difficult to alter. The support learning model is utilized to help routing nodes progressively select increasingly trusted and productive routing connections. The proposed work introduces a Trust Based Efficient Blockchain Linked Routing Method (TbEBCLRM) for a system of trusted and untrusted nodes. The proposed method utilizes blockchain method to improve security in the ad hoc networks and to avoid malicious activities during communication is initiated. The proposed method is compared with the traditional methods and the results show that the proposed method exhibits better performance in terms of accuracy, security level, trust level and energy consumption.

Jan Kotráš

Tato diplomová práce se zabývá technologii blockchain se zaměřením na konsenzus protokoly, zvláště protokoly typu proof-of-stake. V této práci naleznete popis těchto protokolů následovaný popisem konsenzu v technologii blockchain. Prvotní kapitoly detailněji popisují a porovnávají jednotlivé proof-of-stake protokoly na základě teoretických znalostí. Druhá část práce se zaobírá návrhem a implementací testbedu, který je následně použitý pro praktické porovnání proof-of-stake protokolů. V závěrečné částí práce je diskutováno nad zjištěnými výsledky pozorováním testbedu a zjištěnými vlatnostmi protokolů. Na tomto základě práce ve svém konci naznačuje další směřování consesus protokolů, ba jejich případné zlepšení, a zvláště proof-of-stake typu protokolů.

Zisang Xu, Feng Li, Han Deng, Minfu Tan · 6 authors

With the rapid development of mobile networks, there are more and more application scenarios that require group communication. For example, in mobile edge computing, group communication can be used to transmit messages to all group members with minimal resources. The group key directly affects the security of the group communication. Most existing group key agreement protocols are often flawed in performance, scalability, forward or backward secrecy, or single node failure. Therefore, this paper proposes a blockchain-based authentication and dynamic group key agreement protocol. With our protocol, each group member only needs to authenticate its left neighbor once to complete the authentication, which improved authentication efficiency. In addition, our protocol guarantees the forward secrecy of group members after joining the group and the backward secrecy of group members after leaving the group. Based on blockchain technology, we solve the problem of single node failure. Furthermore, we use mathematics to prove the correctness and security of our protocol, and the comparison to related protocols shows that our protocol reduces computation and communication costs.

Chin‐Ling Chen, Yong‐Yuan Deng, Wei Weng, Hongyu Sun · 5 authors

In recent years, blockchain-related technologies and applications have gradually emerged. Blockchain technology is essentially a decentralized database maintained by the collective, and it is now widely applied in various fields. At the same time, with the growth of medical technology, medical information is becoming increasingly important in terms of patient identity background, medical payment records, and medical history. Medical information can be the most private information about a person, but due to issues such as operation errors within the network or a hacking attack by a malicious person, there have been major leaks of sensitive personal information in the past. In any case, this has become an issue worth studying to ensure the privacy of patients and protect these medical materials. On the other hand, under the current medical system, the patient’s EMR (electronic medical record) cannot be searched across the hospital. When the patient attends the hospital for treatment, repeated examinations will occur, resulting in a waste of medical resources. Therefore, we propose a blockchain-based secure inter-hospital EMR sharing system in this article. Through the programmatic authorization mechanism by smart contracts, the security of EMR is guaranteed. In addition to the essential mutual authentication, the proposed scheme also provides and guarantees data integrity, nonrepudiation, user untraceability, forward and backward secrecy, and resistance to replay attack.

Cherukupalli Veda Vyasa Aditya, Rajesh Kannan Megalingam

Zero knowledge proof is a powerful cryptographic protocol that is utilized to establish data security whilst ensuring and maintaining user anonymity. ZKP has relatively less complex computational requirements as compared to the other protocols for authentication. Conventional authentication schemes are susceptible to attacks such as MiTM, IP spoofing, DoS, replay and other eavesdropping based attacks, when the data is shared across an untrusted network. This paper shows an approach to ensure authentication of a device over an untrusted network whilst maintaining and safeguarding user credentials, by using the concepts of ZKP protocol.

Tatsuya Sasaki, Daiki Miyahara, Takaaki Mizuki, Hideaki Sone

In 2009, Gradwohl, Naor, Pinkas, and Rothblum proposed physical zero-knowledge proof protocols for Sudoku. That is, for a puzzle instance of Sudoku, their excellent protocols allow a prover to convince a verifier that there is a solution to the Sudoku puzzle and the prover knows it, without revealing any information about the solution. The possible drawback is that the existing protocols have an extractability error with a non-zero probability, or need special cards (such as scratch-off cards). Thus, in this study, we propose new protocols to perform zero-knowledge proof of knowledge for Sudoku using a normal deck of playing cards with no extractability error. Our protocols can be easily implemented by humans with a reasonable number of playing cards.

Myeonghyun Kim, Sungjin Yu, Joonyoung Lee, Yohan Park · 5 authors

In the traditional electronic health record (EHR) management system, each medical service center manages their own health records, respectively, which are difficult to share on the different medical platforms. Recently, blockchain technology is one of the popular alternatives to enable medical service centers based on different platforms to share EHRs. However, it is hard to store whole EHR data in blockchain because of the size and the price of blockchain. To resolve this problem, cloud computing is considered as a promising solution. Cloud computing offers advantageous properties such as storage availability and scalability. Unfortunately, the EHR system with cloud computing can be vulnerable to various attacks because the sensitive data is sent over a public channel. We propose the secure protocol for cloud-assisted EHR system using blockchain. In the proposed scheme, blockchain technology is used to provide data integrity and access control using log transactions and the cloud server stores and manages the patient's EHRs to provide secure storage resources. We use an elliptic curve cryptosystems (ECC) to provide secure health data sharing with cloud computing. We demonstrate that the proposed EHR system can prevent various attacks by using informal security analysis and automated validation of internet security protocols and applications (AVISPA) simulation. Furthermore, we prove that the proposed EHR system provides secure mutual authentication using BAN logic analysis. We then compare the computation overhead, communication overhead, and security properties with existing schemes. Consequently, the proposed EHR system is suitable for the practical healthcare system considering security and efficiency.

Vanya Cherneva, Jerry L. Trahan

A key communication technology in smart cities and smart buildings for automation is RFID. Proving the simultaneous presence of a group of RFID-tagged objects is a practical need in many application areas within this domain. Some examples of this include vehicle fleets, smart parking, safety in public places (smart cities), security and access control (smart buildings), and asset location (supply chain system, health care industry). Security, privacy, and efficiency are central issues when designing such a grouping-proof protocol. This work is motivated by Sundaresan et al.'s grouping-proof protocol, which applies zero-knowledge techniques. In this paper, we propose a lightweight, offline, serial-dependency grouping-proof protocol. Compared to existing grouping-proof protocols, our scheme improves on efficiency, scalability, security, and communication cost. It resists well-known attacks on grouping-proofs including tag/reader impersonation, tracking, replay, desynchronization, and message integrity.

Ping Li, Shengjun Li, Hongyang Yan, Lishan Ke · 6 authors

Secret sharing has been study for many years and has had a number of real-word applications. There are several methods to construct the secret-sharing schemes. One of them is based on coding theory. In this work, we construct a secret-sharing scheme that realizes an access structure by using linear codes, in which any element of the access structure can reconstruct the secret key. We prove that our scheme is a multiprover zero-knowledge proof system in the random oracle model, which shows that a passive adversary gains no information about the secret key. Our scheme is also a leakage-resilient secret-sharing scheme (LRSS) in the bounded-leakage model, which remain provably secure even if the adversary learns a bounded amount of leakage information about their secret key. As an application, we propose a new group identification protocol (GID-scheme) from our LRSS. We prove that our GID-scheme is a leakage-resilient scheme. In our leakage-resilient GID-scheme, the verifier believes the validity of qualified group members and tolerates l bits of adversarial leakage in the distribution protocol, whereas for unqualified group members, the verifier cannot believe their valid identifications in the proof protocol.

Yongle Chen, Xiaojian Wang, Yuli Yang, Hong Li

Advanced wireless technology in Internet of Things (IoT) devices is increasing and facing various security threats. The authentication of IoT devices is the first line of defense for the wireless network. Especially in a Wi-Fi network, the existing authentication methods mainly use a password or digital certificate, these methods are inconvenient to manage due to certificate issuance or prone to be attacked because passwords are easily cracked. In this paper, we propose a location-aware authentication scheme using smart contracts to ensure that IoT devices can securely perform Wi-Fi network authentication. The scheme adopts the concept of secondary authentication and consists of two phases: the registration phase, which is mainly designed to complete the generation of the public and private keys, and to link the device information with its related device information; the authentication phase, which is mainly designed to determine whether the requesting device is within a legal location range. We use the smart contract to ensure the credibility and irreparability of the authentication process. Analysis of the attack model and the attacks at different stages proves that this certification scheme is assured, and the simulation results show that the overhead introduced by this scheme is acceptable, this scheme can provide greater security for the Wi-Fi authentication of IoT devices.

Fabian Bendun

In this thesis, we present novel methods for verifying, implementing and specifying protocols. In particular, we focus properties modeling data protection and the protection of privacy. In the first part of the thesis, the author introduces protocol verification and presents a model for verification that encompasses so-called Zero-Knowledge (ZK) proofs. These ZK proofs are a cryptographic primitive that is particularly suited for hiding information and hence serves the protection of privacy. The here presented model gives a list of criteria which allows the transfer of verification results from the model to the implementation if the criteria are met by the implementation. In particular, the criteria are less demanding than the ones of previous work regarding ZK proofs. The second part of the thesis contributes to the area of protocol implementations. Hereby, ZK proofs are used in order to improve multi-party computations. The third and last part of the thesis explains a novel approach for specifying data protection policies. Instead of relying on policies, this approach relies on actual legislation. The advantage of relying on legislation is that often a fair balancing is introduced which is typically not contained in regulations or policies.

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Identity is a tool that identifies a person or group and ensures that they are recognized by others. Personalidentification cards issued by the states to people contain specific information about the person given.Identity systems used for centuries are now digitalized, ID cards with chips and passports with chipshave entered our lives. In the past, only information such as name, surname and place of birth wereincluded in ID cards with chips and passports. But today, in addition to our personal information, itincludes our biometric information such as fingerprints, iris, digital signatures. Blockchain technology,which has entered our lives with the financial sector, offers application areas in different sectors andsubjects. Some of these are IoT (internet of things), security and reliability systems, copyrights, publicand health sectors. In this study, it has been mentioned about the advantages and the features obtainedby using blockchain technology in identity management. The purpose of this study; It is to ensure thesafe use of identity information thanks to the features provided by the block chain such as distributeddatabase called DLT (distributed ledger technology), peer-to-peer transmission, transparency andirreversible records. Also in this study, a software that can simulate blockchain technology was createdand an Android application that reads data with NFC (Near Field Communication) technology wasdeveloped. Thus, the process of adding the data in the ID card or passport to the block chain by readingthe data from NFC with the Android application can be performed.

Sébastien Canard, Adela Georgescu, Guillaume Kaim, Adeline Roux-Langlois · 5 authors

No abstract is available for this record.

Michele Ciampi, Roberto Parisella, Daniele Venturi

We study adaptive security of delayed-input Sigma protocols and non-interactive zero-knowledge (NIZK) proof systems in the common reference string (CRS) model. Our contributions are threefold: We exhibit a generic compiler taking any delayed-input Sigma protocol and returning a delayed-input Sigma protocol satisfying adaptive-input special honest-verifier zero knowledge (SHVZK). In case the initial Sigma protocol also satisfies adaptive-input special soundness, our compiler preserves this property. We revisit the recent paradigm by Canetti et al. (STOC 2019) for obtaining NIZK proof systems in the CRS model via the Fiat-Shamir transform applied to so-called trapdoor Sigma protocols, in the context of adaptive security. In particular, assuming correlation-intractable hash functions for all sparse relations, we prove that Fiat-Shamir NIZKs satisfy either: (i) Adaptive soundness (and non-adaptive zero knowledge), so long as the challenge is obtained by hashing both the prover’s first round and the instance being proven; (ii) Adaptive zero knowledge (and non-adaptive soundness), so long as the challenge is obtained by hashing only the prover’s first round, and further assuming that the initial trapdoor Sigma protocol satisfies adaptive-input SHVZK. We exhibit a generic compiler taking any Sigma protocol and returning a trapdoor Sigma protocol. Unfortunately, this transform does not preserve the delayed-input property of the initial Sigma protocol (if any). To complement this result, we also give yet another compiler taking any delayed-input trapdoor Sigma protocol and returning a delayed-input trapdoor Sigma protocol with adaptive-input SHVZK.

Maede Hojjati, Alireza Shafieinejad, Halim Yanıkömeroğlu

Subscriber authentication is a primitive operation in mobile networks required by each operator prior to offering any service to end users. In this paper, we propose a novel blockchain-based Authentication and Key Agreement (AKA) protocol for roaming services in 5G networks. Each Home Network (HN) creates its own smart contract and publishes its address to inform other operators who want to offer roaming services to HN subscribers. All subsequent communication between the HN and Serving Network (SN) is done by calling the function of this smart contract. The proposed protocol eliminates the need for a secure channel between the HN and SN, which is a primary requirement of current 5G AKA protocols. In practice, a secure channel requires the HN and SN to establish a secure session before running the AKA protocol. Further, the proposed protocol leverages the benefits of blockchain, such as auditable log, decentralized architecture, and the prevention of Denial of Service (DoS) attacks. Furthermore, we provide a security proof of the protocol through formal verification using ProVerif. The results show that our scheme tends to preserve user privacy and at the same time provides mutual authentication of the participants. Finally, our evaluation of the Ethereum blockchain shows that the protocol is efficient in terms of both transaction and execution costs.

Xinyin Xiang, Mingyu Wang, Weiguo Fan

The growth of electronic healthcare (e-health) systems is promoted by the evolution of Internet of Things (IoT) technology, as this new environment provides a variety of alternatives for medical data collection. Traditional authentication models in e-health systems cannot be applied directly to scenarios requiring low-latency, real-time services. Providing a variety of means for data transmission is considered an important method to achieve effective control in e-health systems. However, this new approach also leads to security and privacy concerns as increasingly flexible communication services are introduced. Achieving effective authentication of medical data for different users while providing security guarantees in e-health systems is an interesting problem. In this paper, we present a permissioned blockchain-based identity management and user authentication (PBBIMUA) scheme for the e-health environment. Our scheme satisfies the extensive security requirements of medical data. An evaluation and security analysis show that performance, in terms of lightweight construction and lower network latency with high security standards, is improved in comparison to known methods. The experimental results show that the system has good efficiency.

Seunghwan Son, Joonyoung Lee, Myeonghyun Kim, Sungjin Yu · 6 authors

Telecare medical information system (TMIS) implemented in wireless body area network (WBAN) is convenient and time-saving for patients and doctors. TMIS is realized using wearable devices worn by a patient, and wearable devices generate patient health data and transmit them to a server through a public channel. Unfortunately, a malicious attacker can attempt performing various attacks through such a channel. Therefore, establishing a secure authentication process between a patient and a server is essential. Moreover, wearable devices have limited storage power. Cloud computing can be considered to resolve this problem by providing a storage service in the TMIS environment. In this environment, access control of the patient health data is essential for the quality of healthcare. Furthermore, the database of the cloud server is a major target for an attacker. The attacker can try to modify, forge, or delete the stored data. To resolve these problems, we propose a secure authentication protocol for a cloud-assisted TMIS with access control using blockchain. We employ ciphertext-policy attribute-based encryption (CP-ABE) to establish access control for health data stored in the cloud server, and apply blockchain to guarantee data integrity. To prove robustness of the proposed protocol, we conduct informal analysis and Burrows-Adabi-Needham (BAN) logic analysis, and we formally validate the proposed protocol using automated validation of internet security protocols and applications (AVISPA). Consequently, we show that the proposed protocol provides more security and has better efficiency compared to related protocols. Therefore, the proposed protocol is proper for a practical TMIS environment.

Neha Garg, Mohammad Wazid, Ashok Kumar Das, Devesh Pratap Singh · 6 authors

The Internet of Medical Things (IoMT) is a kind of connected infrastructure of smart medical devices along with software applications, health systems and services. These medical devices and applications are connected to healthcare systems through the Internet. The Wi-Fi enabled devices facilitate machine-to-machine communication and link to the cloud platforms for data storage. IoMT has the ability to make accurate diagnoses, with fewer mistakes and lower costs of care. IoMT with smartphone applications permits the patients to exchange their health related confidential and private information to the healthcare experts (i.e., doctors) for the better control of diseases, and also for tracking and preventing chronic illnesses. Due to insecure communication among the entities involved in IoMT, an attacker can tamper with the confidential and private health related information for example an attacker can not only intercept the messages, but can also modify, delete or insert malicious messages during communication. To deal this sensitive issue, we design a novel blockchain enabled authentication key agreement protocol for IoMT environment, called BAKMP-IoMT. BAKMP-IoMT provides secure key management between implantable medical devices and personal servers and between personal servers and cloud servers. The legitimate users can also access the healthcare data from the cloud servers in a secure way. The entire healthcare data is stored in a blockchain maintained by the cloud servers. A detailed formal security including the security verification of BAKMP-IoMT using the widely-accepted Automated Validation of Internet Security Protocols and Applications (AVISPA) tool is performed to demonstrate its resilience against the different types of possible attack. The comparison of BAKMP-IoMT with relevant existing schemes is conducted which identifies that the proposed system furnishes better security and functionality, and also needs low communication and computational costs as compared to other schemes. Finally, the simulation of BAKMP-IoMT is conducted to demonstrate its impact on the performance parameters.