Bilinear pairing is a fundamental operation that is widely used in cryptographic algorithms (e.g., identity-based cryptographic algorithms) to secure IoT applications. Nonetheless, the time complexity of bilinear pairing is$O(n^{3})$, making it a very time-consuming operation, especially for resource-constrained IoT devices. Secure outsourcing of bilinear pairing has been studied in recent years to enable computationally weak devices to securely outsource the bilinear pairing to untrustworthy cloud servers. However, the state-of-art algorithms often require to precompute and store some values, which results in storage burden for devices. In the Internet of Things, devices are generally with very limited storage capacity. Thus, the existing algorithms do not fit the IoT well. In this article, we propose a secure outsourcing algorithm of bilinear pairings, which does not require precomputations. In the proposed algorithm, the outsourcer side’s efficiency is significantly improved compared with executing the original bilinear pairing operation. At the same time, the privacy of the input and output is ensured. Also, we apply the Ethereum blockchain in our outsourcing algorithm to enable fair payments, which ensures that the cloud server gets paid only when he correctly accomplished the outsourced work. The theoretical analysis and experimental results show that the proposed algorithm is efficient and secure.
Shiwen Zhang, Tingting Yao, Voundi Koe Arthur Sandor, Tien‐Hsiung Weng · 6 authors
Online social networks (OSNs) are nowadays an important field of applications thanks to the recent surge in online interaction. However, the illegal disclosure of user's private data can cause damaging consequences and even threaten the safety of users' life. The privacy issues of OSNs have become a matter of great concern for many people. In recent years, there are some research works to address this privacy issue, yet they do not always focus on providing the normal social network services for users, such as data sharing, data retrieval and data access services. Therefore, it is a challenge to ensure the security of sensitive data while providing efficient and privacy-preserving social network services for users. In this paper, we propose a novel blockchain-based privacy-preserving framework for online social networks, called BPP. Combined blockchain and public-key cryptography technique, the BPP framework can achieve secure data sharing, data retrieving, and data accessing with fairness and without worrying about potential damage to users' interest. Specifically, based on blockchain and public key encryption with keyword search technique, a secure, fair and efficient keyword search algorithm is proposed, with which the BBP framework realises privacy preservation of user's query and then obtain accurate query results with assurance and without needing for any further verification operation in online social network. Finally, we implement a prototype of our framework and deploy it to a locally simulated network. The extensive experiments and security analysis demonstrate the security, efficacy and efficiency of our proposed framework.
The fifth generation (5G) cellular network provides users with high-quality services due to its high transmission rate and low latency. It will support Internet of Things (IoT) devices and enable new applications in health, banking, education, etc. Security is essential in this network because vulnerabilities may be exploited to disrupt these applications which may directly impact our life. Authentication and key agreement (AKA) and handover (HO) are usually the target of cyberattacks in any cellular network. On the other hand, blockchain is a peer-to-peer network that aims to maintain an immutable and secure ledger. This new technology will be used widely to secure many applications. This paper aims to develop an efficient and secure AKA scheme and uniform handover protocol for 5G network using blockchain. The home network (HN) is not involved in the AKA scheme and HO protocol to protect the HN from attacks, such as denial of service (DoS) attacks, and also lower the communication and computation overhead. Moreover, our HO protocol is uniform in the sense that it can be used for all HO scenarios. The protocol is also efficient because it requires exchanging a few amount of data. It can also achieve forward/backward secrecy. Furthermore, the blockchain is used to verify the public keys of the network nodes which is necessary to secure our AKA scheme and HO protocol. It also records the locations of the users which is necessary for the functionality of the network. Our evaluations demonstrate that the proposed HO protocol is secure, uniform, and can achieve the forward/backward secrecy. Furthermore, our AKA scheme requires lower computation and computation overhead comparing to the existing schemes, and preserves the energy of the limited-energy mobile devices.
In the existing Electronic Health Records (EHRs), the medical information of patients is completely controlled by various medical institutions. As such, patients have no dominant power over their own EHRs. These personal data are not only inconvenient to access and share, but are also prone to cause privacy disclosure. The blockchain technology provides a new development direction in the medical field. Blockchain-based EHRs are characterized by decentralization, openness and non-tampering of records, which enable patients to better manage their own EHRs. In order to better protect the privacy of patients, only designated receivers can access EHRs, and receivers can authenticate the sharer to ensure that the EHRs are real and effective. In this study, we propose an identity-based signcryption scheme with multiple authorities for multiple receivers, which can resist N-1 collusion attacks among N authorities. In addition, the identity information of receivers is anonymous, so the relationship between them and the sharer is not disclosed. Under the random oracle model, it was proved that our scheme was secure and met the unforgeability and confidentiality requirements of signcryption. Moreover, we evaluated the performance of the scheme and found that it had the moderate signcryption efficiency and excellent signcryption attributes.
With the rapid development of cloud computing, a large number of web services have been emerging quickly, which brings a heavy burden for users to choose the services they preferred. In order to suggest web services for users, recommendation algorithms are needed and many of them have been investigated recently. However, most of the existing recommendation schemes are based on centralized historical data, which may lead to single point of failure. Generally, the data contains a lot of sensitive information that cloud may expose the privacy of users, which makes most cloud platforms reluctant to share their own data. In order to solve the above issues, the secure data sharing among cloud platforms is necessary for better recommendation, which can maximize the profits. In this paper, we propose a blockchain-assisted collaborative service recommendation scheme ($BC - SRDS$). Specifically, we adopt the ciphertext-policy attribute-based encryption (CP-ABE) algorithm to encrypt the data, which ensures the data confidentiality and realizes secure data sharing. Then, we utilize the blockchain to share data, such that the DoS attack, DDoS attack and single point of failure can be avoided. Meanwhile, the data integrity, tampering-proof of data are guaranteed through the blockchain. And we use locality-sensitive hashing algorithm to recommend the services for users. Finally, it is proved through the security analysis that$BC - SRDS$is capable of achieving data confidentiality, data integrity and tampering-proof. A series of experiments show that$BC - SRDS$achieves better recommendation accuracy compared with the existing schemes.
Jiashun Zhang, Gang Xu, Xiu‐Bo Chen, Haseeb Ahmad · 6 authors
With the rapid development of cloud computing technology, cloud services have now become a new business model for information services. The cloud server provides the IT resources required by customers in a self-service manner... | Find, read and cite all the research you need on Tech Science Press
Nasibeh Mohammadzadeh, Sadegh Dorri Nogoorani, José L. Muñoz
Invoice factoring is a very useful tool for developing businesses that face liquidity problems. The main property that a factoring system needs to fulfill is to prevent an invoice from being factored twice. In order to prevent double factoring, many factoring ecosystems use one or several centralized entities to register factoring agreements. However, this puts a lot of power in the hands of these centralized entities and makes it difficult for users to dispute situations in which factoring data is unavailable, wrongly recorded or manipulated by negligence or on purpose. In this article, we propose an architecture for invoice factoring registration based on a public blockchain. To solve the aforementioned drawbacks, we replace the trusted third parties for factoring registration with a smart contract. Using a smart contract, we record digital evidence of the terms and conditions of factoring agreements in explicit detail, allowing auditability and dispute resolution. Relevant information is highly available on the blockchain while its privacy is protected. The registration is optimal, since it needs only one blockchain transaction and one key-value storage per invoice factoring.
Data supervision is an effective method to ensure the legality of user data on blockchain. However, the massive growth of data makes it difficult to achieve data supervision in existing blockchain applications. Also, data supervision often leads to problems such as disclosure of transaction data and user privacy information. To address these issues, this paper proposes a privacy‐preserving blockchain supervision system (BSS) in the multiparty setting, where a supervision chain is introduced to realize data supervision on blockchain. All sensitive information such as user information in the supervising data is encrypted by the attribute‐based encryption (ABE) technology, so that both privacy protection and access control on user data can be achieved. Theoretical analysis and comparison show that the proposed BSS scheme is efficient, and experimental analysis indicates the practicality of our BSS scheme.
With the development of blockchain technology, more and more applications need out-of-chain data. Thus, blockchain oracles have become an important bridge for transferring data on and off the chain. This paper studies the mainstream blockchain oracles scheme, summarizes the shortcomings of the existing schemes and proposes a new blockchain oracle scheme based on BLS (Bohen-Lynn-Shacham) aggregation signature to ensure that off-chain data can be transferred into the blockchain in a trusted and reliable way. Specifically, the scheme uses multiple blockchain oracles to avoid the single point of failure or even a small number of malicious oracles, and improve the credibility of data. At the same time, it not only uses BLS aggregate signature to reduce the storage cost and communication overhead, but also uses commitment mechanisms to ensure the reliability and authenticity of the data. Besides, the simulation results show that the scheme can meet the practical application requirements.
Group signature schemes play a vital role in protecting identity privacy of a member of a group who signs a message using the group signature. However, in the existing group signature schemes the centralized group manager has control over all the participants, and these managers can be malicious. They may take a biased decision when there is a dispute among the group members or while revealing the identity of a group member. To overcome the trust issues related to centralized group managers and to improve user privacy, a decentralized group signature scheme (DGSS) is proposed by decentralizing the role of the group manager. The proposed scheme will be more suitable for decentralized environments like a blockchain. Security analysis along with the proof of correctness is also provided for the proposed scheme. A framework for a blockchain-based e-auction protocol using the DGSS is also proposed in this paper.
Open access
Blockchain Technology Applications and Security
Cryptography and Data Security
Advanced Steganography and Watermarking Techniques
The maintenance and sharing of electronic medical records are one of the essential tasks in the medical treatment combination. Traditional cloud-based electronic medical record storage system is difficult to realize data security sharing. The tamper resistance and traceability of blockchain technology provide the possibility for the sharing of highly sensitive medical data. This paper proposes a safe sharing scheme of stroke electronic medical records based on the consortium blockchain. The scheme adopts the storage method of ciphertext of medical records stored in the cloud and index of medical records stored on the blockchain. The privacy protection mechanism proposed in this paper innovatively combines proxy reencryption and searchable encryption which supports patient pseudoidentity search. The mechanism could achieve controllable sharing of medical records and precise search. According to the organizational characteristics of the stroke medical treatment combination, this paper proposes an improved Practical Byzantine Fault Tolerance mechanism to reach a consensus between consensus nodes. Then, the proposed scheme is analyzed and evaluated from three aspects of medical record integrity, user privacy, and data security. The results show that the scheme can not only ensure the privacy of patient identity information and private key data but also resist the tampering and deletion attacks of internal and external malicious nodes on the medical record data. Therefore, the proposed scheme is conducive to the improvement of the timeliness of stroke treatment and the safe sharing of electronic medical records in stroke medical treatment combination.
In order to ensure the security of logistics information and to query information quickly and efficiently, using searchable encryption algorithms, combined with the characteristics of the blockchain, a searchable and encrypted logistics information blockchain data query algorithm is proposed. First, the logistics information is divided into multiple data files, encrypted with an asymmetric searchable encryption algorithm, and then stored in the cloud server. The keyword index value is extracted from each data file and uploaded to the blockchain. This solution can be used at any time Update and query data. Finally, analyze the correctness, completeness and safety of the scheme of this article, which proves the feasibility of this scheme.
Stefan Dziembowski, Grzegorz Fabiański, Sebastian Faust, Siavash Riahi
Blockchain is a disruptive new technology introduced around a decade ago. It can be viewed as a method for recording timestamped transactions in a public database. Most of blockchain protocols do not scale well, i.e., they cannot process quickly large amounts of transactions. A natural idea to deal with this problem is to use the blockchain only as a timestamping service, i.e., to hash several transactions tx_1,…,tx_m into one short string, and just put this string on the blockchain, while at the same time posting the hashed transactions tx_1,…,tx_m to some public place on the Internet ("off-chain"). In this way the transactions tx_i remain timestamped, but the amount of data put on the blockchain is greatly reduced. This idea was introduced in 2017 under the name Plasma by Poon and Buterin. Shortly after this proposal, several variants of Plasma have been proposed. They are typically built on top of the Ethereum blockchain, as they strongly rely on so-called smart contracts (in order to resolve disputes between the users if some of them start cheating). Plasmas are an example of so-called off-chain protocols. In this work we initiate the study of the inherent limitations of Plasma protocols. More concretely, we show that in every Plasma system the adversary can either (a) force the honest parties to communicate a lot with the blockchain, even though they did not intend to (this is traditionally called mass exit); or (b) an honest party that wants to leave the system needs to quickly communicate large amounts of data to the blockchain. What makes these attacks particularly hard to handle in real life is that these attacks do not have so-called uniquely attributable faults, i.e. the smart contract cannot determine which party is malicious, and hence cannot force it to pay the fees for the blockchain interaction. An important implication of our result is that the benefits of two of the most prominent Plasma types, called Plasma Cash and Fungible Plasma, cannot be achieved simultaneously. Besides of the direct implications on real-life cryptocurrency research, we believe that this work may open up a new line of theoretical research, as, up to our knowledge, this is the first work that provides an impossibility result in the area of off-chain protocols.
Tooba Faisal, Mischa Döhler, Simone Mangiante, Diego López
It is widely expected that future networks of 6G and beyond will deliver on the unachieved goals set by 5G. Technologies such as Internet of Skills and Industry 4.0 will become stable and viable, as a direct consequence of networks that offer sustained and reliable mobile performance levels. The primary challenges for future technologies are not just low-latency and high-bandwidth. The more critical problem Mobile Service Providers (MSPs) will face will be in balancing the inflated demands of network connections and customers' trust in the network service, that is, being able to interconnect billions of unique devices while adhering to the agreed terms of Service Level Agreements (SLAs). To meet these targets, it is self-evident that MSPs cannot operate in a solitary environment. They must enable cooperation among themselves in a manner that ensures trust, both between themselves as well as with customers. In this study, we present the BEAT (Blockchain-Enabled Accountable and Transparent) Infrastructure Sharing architecture. BEAT exploits the inherent properties of permissioned type of distributed ledger technology (i.e., permissioned distributed ledgers) to deliver on accountability and transparency metrics whenever infrastructure needs to be shared between providers. We also propose a lightweight method that enables device-level accountability. BEAT has been designed to be deployable directly as only minor software upgrades to network devices such as routers. Our simulations on a resource-limited device show that BEAT adds only a few seconds of overhead processing time -- with the latest state-of-the-art network devices, we can reasonably anticipate much lower overheads.
Umer Majeed, Latif U. Khan, Abdullah Yousafzai, Zhu Han · 6 authors
Federated Learning (FL) relies on on-device training to avoid the migration of devices’ data to a centralized server to address privacy leakage. Moreover, FL is feasible for scenarios (e.g., autonomous cars) where an enormous amount of data is generated every day. Transferring only local model updates in the case of FL is highly communication-efficient compared to transferring all data in the case of centralized machine learning (ML). Although FL offers many advantages, it also has some challenges. A malicious aggregation server can infer device information via local model updates. Another downside of FL is the centralized aggregation server that can malfunction due to an attack or physical damage. To address these issues, we propose a novel Structured Transparency empowered cross-silo Federated Learning on the Blockchain (ST-BFL) framework. In ST-BFL, homomorphic encryption, FL-aggregators, FL-verifiers, and smart contract are employed, which satisfy various structured transparency components, such as input privacy, output privacy, output verification, and flow governance. We present the framework architecture, algorithms, and sequence diagram of our ST-BFL framework to show how different entities interact in ST-BFL for the FL process. We also present a simplified class diagram of ST-BFL’s smart contract for an FL task. Finally, we perform a simulation to analyze our framework from the perspective of aggregation time, accuracy, and storage size. The qualitative and quantitative evaluation shows that ST-BFL has the same accuracy as traditional FL. However, ST-BFL provides input privacy, output privacy, input verification, output verification, and flow governance at the expense of relatively higher computation and communication costs than traditional FL.
Jiansheng Zhang, Yang Xin, Gao Yu-long, Xiaohui Lei · 5 authors
Internet of Things (IoT) has been widely used in various fields of our daily life in the past years. Obviously, in the future, the significance of its security will be more evident and enormous. However, there are still many security issues in the IoT, which makes it vulnerable to be attacked easily by some potential factors. Targeting at these issue, in this paper, we propose a secure access management scheme in IoT based on blockchain. Firstly, in our work, by using the Decisional Learning with Error (DLWE) problem, we propose a secure Key-policy Attribute-based Encryption (KP-ABE) scheme, it can implement fine-grained access control in IoT. Secondly, we use blockchain to solve the authentication and access management challenges. In addition, the smart contract in blockchain can process transactions automatically, which greatly reduces the management cost and running time for this scheme. Last but not the least, we further analyze the security of our proposed scheme. The result shows that our scheme can resist some common attacks in IoT, and it is more secure and efficient.
Antonio M. Larriba, Aleix Cerdà i Cucó, José M. Sempere, Damián López
Voting systems are as useful as people are willing to use them. Although many electronic election schemes have been proposed through the years, and some real case scenarios have been tested, people still do not trust electronic voting. Voting is not only about technological challenges but also about credibility, therefore, we propose a voting system focused on trust. We introduce political parties as active partners in the elections as a mechanism to encourage more traditional electors to participate. The system we propose here preserves elector’s privacy, it operates publicly through a blockchain and it is auditable by third parties.
Medical files can help people prevent diseases, increase cure rates, promote medical development and help solve major public health crises. However, medical files are strongly private. It is an urgent problem needed to be solved that how to share medical files with privacy and data security. The existing models based on the centralized certificate authority is a feasible method, but it is possible to experience a single point failure. Besides there is a mismatch between the models and real-life scenario since they are only suitable for single patient. Therefore, this paper proposes a practical medical file sharing scheme based on blockchain and decentralized attribute-based encryption. The blockchain is used to record application and grant of authorizations. Smart contracts provide an interactive platform for all users in the system. By utilizing decentralized attribute-based encryption, fine-grained access control of medical files is carried out to ensure privacy and security as well as avoiding single point failure. Attribute-based algorithm that support multi-person democratic decision making and dynamic personnel changes are designed to make the model much closer to the real scene. Finally, through security, performance and comparative analysis with other solutions, the scheme in this paper can meet the needs of real-life scenarios in terms of security and practicability, and provides a new practical model for medical file sharing.