Verifiable Random Function Research Articles

An Anonymous Verifiable Random Function with Applications in Blockchain

Verifiable random function is a powerful function that provides a noninteractively public verifiable proof for its output. Recently, verifiable random function has found essential applications in designing secure consensus protocols in blockchain. How to construct secure and practical verifiable random functions has also attracted more and more attention. In this paper, we propose a practical anonymous verifiable random function. Security proofs show that the proposed anonymous verifiable random function achieves correctness, anonymity, uniqueness, and pseudorandomness. In addition, we show a concrete application of our proposed anonymous verifiable random function in blockchain to improve the consensus mechanism for Hyperledger fabric. Finally, we implement the proposed anonymous verifiable random function and evaluate its performance. Test results show that the proposed anonymous verifiable random function supports faster computing operations and has a smaller proof size.

A Lightweight and Attack-Proof Bidirectional Blockchain Paradigm for Internet of Things

Diverse technologies, such as machine learning and big data, have been driving the prosperity of the Internet of Things (IoT) and the ubiquitous proliferation of IoT devices. Consequently, it is natural that IoT becomes the driving force to meet the increasing demand for frictionless transactions. To secure transactions in IoT, blockchain is widely deployed since it can remove the necessity of a trusted central authority. However, the mainstream blockchain-based IoT payment platforms, dominated by Proof-of-Work (PoW) and Proof-of-Stake (PoS) consensus algorithms, face several major security and scalability challenges that result in system failures and financial loss. Among the three leading attacks in this scenario, double-spend attacks and long-range attacks threaten the tokens of blockchain users, while eclipse attacks target Denial of Service. To defeat these attacks, a novel bidirectional-linked blockchain (BLB) using chameleon hash functions is proposed, where bidirectional pointers are constructed between blocks. Furthermore, a new committee members auction (CMA) consensus algorithm is designed to improve the security and attack resistance of BLB while guaranteeing high scalability. In CMA, distributed blockchain nodes elect committee members through a verifiable random function. The smart contract uses Shamir’s secret-sharing scheme to distribute the trapdoor keys to committee members. To better investigate BLB’s resistance against double-spend attacks, an improved Nakamoto’s attack analysis is presented. In addition, a modified entropy metric is devised to measure eclipse attack resistance across different consensus algorithms. Extensive evaluation results show the superior resistance against attacks and demonstrate high scalability of BLB compared with current leading paradigms based on PoS and PoW.

Blockchain-based random auditor committee for integrity verification

With the popularity of cloud storage, integrity verification for outsourced data has attracted more and more attention. The majority of existing research works rely on a unique third-party auditor (TPA) or fixed TPAs to audit the integrity of outsourced data, and thus they are vulnerable to DoS and collusion attacks as the TPA is not completely trusted. To conquer this problem, a blockchain-based random auditor committee is proposed to replace the fixed TPAs for the integrity verification (call BRAC scheme for short). The proposed blockchain consensus algorithm utilizes a verifiable random function (VRF) to select the third-party auditor committee (TPAC) which performs contract verification. The leader of TPAs (LTPA) packs the verification proof into a blockchain called verification chain. The main idea is employing the output of a VRF for leader election to make it probabilistic, such that specific nodes cannot be targeted in advance and a certain fraction of the nodes being malicious can be tolerated. We present rigorous security analysis to demonstrate the security of the proposed scheme. Meanwhile, the comprehensive performance evaluation shows that the proposed scheme improves the performance of data integrity verification effectively.

A Blockchain-Based Authentication Scheme and Secure Architecture for IoT-Enabled Maritime Transportation Systems

Although modern Maritime Transportation Systems (MTS) have been extensively benefited from Internet of Things (IoT) technology, but still the risks and challenges in safety and reliability have increased substantially. The involvement of different maritime parties in the marine transportation flow scheduling and management further escalates these challenges. Thus, we need an IoT-based collaborative processing system that unifies the modular structure and integrates multiple modules involved in MTS. Moreover, the need for a shared and controlled access mechanism that cannot be manipulated or tampered by unauthorized parties is also essential requirement in MTS. Blockchain, as an emerging technology, has become a key tool in data security protection because of its non-tampering and non-forgery characteristics. Keeping in view of this aspect, in this paper, an IoT-based collaborative processing system based on blockchain is proposed for marine transportation flow scheduling and management. In addition, we propose a novel consensus mechanism based on Verifiable Random Function (VRF) and reputation voting to reduce the communication cost in blockchain consensus communication process. The proposed scheme has been validated in a simulated environment and the results illustrate that the scheme has obvious effect in resisting replay attack and camouflage attack. Furthermore, the optimized consensus mechanism improves the security by 8% and the transaction processing speed by 6% on the premise that the communication cost is basically unchanged.

Simulatable Verifiable Random Function from the Lwe Assumption

Simulatable Verifiable Random Function from the Lwe Assumption

Bool Network: An Open, Distributed, Secure Cross-Chain Notary Platform

With the advancement of blockchain technology, hundreds of cryptocurrencies have been deployed. The bloom of heterogeneous blockchain platforms brings a new emerging problem: typically, various blockchains are isolated systems, how to securely identify and/or transfer digital properties across blockchains? There are three main kinds of cross-chain approaches: sidechains/relays, notaries, and hashed time-lock contracts. Among them, notary-based cross-chain solutions have the best compatibility and user-friendliness, but they are typically centralized. To resolve this issue, we present Bool Network – an open, distributed, secure cross-chain notary platform powered by MPC-based distributed key management over evolving hidden committees. More specifically, to protect the identities of the committee members, we propose a Ring verifiable random function ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Ring VRF</i> ) protocol, where the real public key of a VRF instance can be hidden among a ring, which may be of independent interest to other cryptographic protocols. Furthermore, all the key management procedures are executed in the TEE, such as Intel SGX, to ensure the privacy and integrity of partial key components. A prototype of the proposed Bool Network is implemented in Rust language, using Polkadot Substrate.

New public blockchain protocol based on sharding and aggregate signatures

Existing blockchains, especially public blockchains, face the challenges of scalability which means the processing capacity will not get better with the addition of nodes, making it somewhat infeasible for mobile computing applications. Some improved technologies are known to speed up processing capacity by shrinking the consensus group, increasing the block capacity and/or shortening the block interval. Even these solutions are met with major problems such as storage limitations and weak security. To face the realistic application scenarios for blockchain technology in the mobile realm, we propose a new public blockchain designed based on sharding, aggregate signature and cryptographic sortition which we call SAC. In SAC, the transaction rate increases with the number of shards while the length of the consensus signature is a constant. Meanwhile, in SAC, the assignment of consensus representatives is controlled by a verifiable random function, which can effectively solve the problem of centralized consensus. In addition, this paper analyzes the performance of SAC to give adequate comparison with other sharding technologies while also giving a rational security analysis. Our experimental results clearly show the potential applicability of this novel blockchain protocol to in mobile computation.

Efficient Continuous Big Data Integrity Checking for Decentralized Storage

Decentralized storage powered by blockchain is becoming a new trend that allows data owners to outsource their data to remote storage resources offered by various storage providers. Unfortunately, unqualified storage providers easily encounter unpredictable downtime due to security threats, such as malicious attacks or system failures, which is unacceptable in many real-time or data-driven applications. As a result, continuous data integrity should be guaranteed in decentralized storage, which ensures that data is intact and available for the entire storage period. However, this requires frequent checking for long time periods and incurs heavy burdens of both communication and computation, especially in a big data scenario. In this paper, we propose an efficient continuous big data integrity checking approach for decentralized storage. We design a data-time sampling strategy that randomly checks the integrity of multiple files at each time slot with high checking probability. Furthermore, to tackle the fairness problem derived from the sampling strategy, we propose a fair approach by designing an arbitration algorithm with the verifiable random function. Security analysis shows the security of our approach under the random oracle model. Evaluation and experiments demonstrate that our approach is more efficient in the big data scenario compared with the state-of-the-arts.

Privacy preserving file auditing schemes for cloud storage using verifiable random function

Users leverage the cloud storage to store data by uploading files to the cloud storage. They can use it to share files to work on collaborative projects. However, during administrative operations by cloud storage service provider (CSSP), there may be some inadvertent corruption of files during data migration and backup. Due to heavy demands, the cloud service provider may not update the desired files immediately when requested by the owner. As a result, a user of the file may receive an obsolete file. To ensure integrity and freshness of files, third party auditing (TPA) services should be supported by CSSP while maintaining the confidentiality of user files and preserving privacy of users. In this paper, three privacy preserving auditing schemes for files stored in cloud has been proposed. Verifiable random function, merkle hash tree and ciphertext-policy attribute-based encryption has been used to achieve the desired goals.

Research and application of hyperledger fabric based on VRF on electronic order

Abstract With the rapid development of information digitization, a large number of electronic orders have also brought a series of problems such as data security and trust. In the face of the ever-increasing demand for electronic data storage, the traditional and conventional storage methods have gradually exposed many problems such as extremely high cost, low efficiency, and difficulty in acceptance. It has become an urgent need to ensure the data security and credibility of electronic orders. solved problem. Aiming at how to ensure the authority and security of electronic documents, through the study of the Hyperledger Fabric consensus mechanism, and at the same time, in order to solve the security risks and processing bottlenecks caused by the use of fixed endorsement nodes in the hyperledger structure to handle all exchanges, the use of A non-interactive, verifiable random endorsement scheme. On the basis of the consensus mechanism of endorsement-sorting-verification, by introducing a candidate set of endorsing nodes, using a verifiable random function to randomly select endorsing nodes and endorsing each order, a non-interactive verifiable random selection of endorsing nodes is realized And parallel endorsement process. Analysis and experiments show that the optimized consensus mechanism has higher security and faster transaction processing speed.

RTChain

Blockchain technology, whose most successful application is Bitcoin, enables non-repudiation and non-tamperable online transactions without the participation of a trusted central party. As a global ledger, the blockchain achieves the consistency of replica stored on each node through a consensus mechanism. A well-designed consensus mechanism, on one hand, needs to be efficient to meet the high frequency of online transactions. For example, the existing electronic payment systems can handle over 50,000 transactions per second (TPS), while Bitcoin can only handle an average of about 3TPS. On the other hand, it needs to have good security and high fault tolerance; that is, in the case when some nodes are captured by adversaries, the network can still operate normally. In this article, we establish a reputation system, called RTChain, to be integrated into the e-commerce blockchain to achieve a distributed consensus and transaction incentives. The proposed scheme has the following advantages. First, an incentive mechanism is used to influence the consensus behavior of nodes and the transaction behavior of users, which in turn influence the reputation scores of both nodes and users. That is, when a node correctly processes a transaction, it will receive the corresponding reputation value as a reward, and the reputation value will be reduced as punishment not only when the node is dishonest and violates the consensus agreement but also the transaction is not completed as required. Just like electronic transactions in the real world, the higher the reputation of the user, the more likely it is to be selected as the transaction partner. A user with a low reputation will be gradually eliminated in our system because it is difficult to complete the transaction. Second, RTChain uses a verifiable random function to generate the leader in each round, which guarantees fairness for all participants and, unlike PoW, does not consume a large amount of computing resources. Then our consensus mechanism selects the nodes with high reputation scores to reduce the number of nodes participating in the consensus, thus improving the consensus efficiency, so that RTChain’s throughput can reach 4,000TPS. Third, we built a reputation chain to implement the distributed storage and management of reputation. Finally, our consensus mechanism is secure against existing attacks, such as flash attacks, selfish mining attacks, eclipse attacks, and double spending attacks, and allows nodes that participate in the consensus to fail, as long as the reputation of the failure node does not exceed one-third of the total reputation. We build a prototype of RTChain, and the experimental results show that RTChain is promising and deployable for e-commerce blockchains.

Statically Aggregate Verifiable Random Functions and Application to E-Lottery

Cohen, Goldwasser, and Vaikuntanathan (TCC’15) introduced the concept of aggregate pseudo-random functions (PRFs), which allow efficiently computing the aggregate of PRF values over exponential-sized sets. In this paper, we explore the aggregation augmentation on verifiable random function (VRFs), introduced by Micali, Rabin and Vadhan (FOCS’99), as well as its application to e-lottery schemes. We introduce the notion of static aggregate verifiable random functions (Agg-VRFs), which perform aggregation for VRFs in a static setting. Our contributions can be summarized as follows: (1) we define static aggregate VRFs, which allow the efficient aggregation of VRF values and the corresponding proofs over super-polynomially large sets; (2) we present a static Agg-VRF construction over bit-fixing sets with respect to product aggregation based on the q-decisional Diffie–Hellman exponent assumption; (3) we test the performance of our static Agg-VRFs instantiation in comparison to a standard (non-aggregate) VRF in terms of costing time for the aggregation and verification processes, which shows that Agg-VRFs lower considerably the timing of verification of big sets; and (4) by employing Agg-VRFs, we propose an improved e-lottery scheme based on the framework of Chow et al.’s VRF-based e-lottery proposal (ICCSA’05). We evaluate the performance of Chow et al.’s e-lottery scheme and our improved scheme, and the latter shows a significant improvement in the efficiency of generating the winning number and the player verification.

Voting-Based Decentralized Consensus Design for Improving the Efficiency and Security of Consortium Blockchain

Since its emergence, blockchain technology has received great attention because of its advantages in terms of decentralization, transparency, traceability, and the ability to be tamper proof. These advantages help blockchain become a better option for fields, such as digital currency and information storage. Specifically, consortium blockchain is preferred by researchers because it provides a certain degree of access control and a supervisory mechanism. However, in real-world applications, blockchain platforms pervasively show bottlenecks, such as ultrahigh energy consumption, time inefficiency, low transaction throughput, vulnerability to targeted attacks, and poor fairness of user profits, which seriously influence the performance of this technology and thus hinder its development and adoption. In this article, we try to enhance the performance of blockchain platforms by optimizing the quality of its core module, known as the consensus algorithm. To do so, we introduce proof of assets and proof of reputation to design a voting-based decentralized consensus (VDC) algorithm for consortium blockchain. Combined with the verifiable random function (VRF), VDC realizes better fairness of user profits and time efficiency with acceptable energy consumption and without sacrificing security. The simulation results show that the proposed algorithm achieves a faster consensus process and better user fairness than existing algorithms while still maintaining a negligible energy cost and adequate security.

Consensus Mechanism of IoT Based on Blockchain Technology

Applying blockchain technology to the Internet of Things (IoT) remains a huge challenge. To meet the actual needs of IoT, a lightweight and high-throughput consensus mechanism, combined with blockchain technology, is proposed in this study. Blockchain nodes use the Diffie–Hellman algorithm for key negotiation. Sensors and blockchain nodes can use the shared key to generate HMAC (Hash-based Message Authentication Code) signatures for sensor-aware transactions and use the Verifiable Random Function to implement block nodes. Offline fast election, which is the node that wins the election, becomes the block node. Machine learning methods are also introduced to identify or remove outliers in the sensor data before such data are uploaded to the chain. Experimental results show that the system throughput synchronously increases as the test load increases. Moreover, when the test load is 800 tps, the system throughput reaches the maximum, close to 600 tps. When the test load exceeds 800 tps, the actual system throughput starts to drop, and approximately 90% of transactions have a delay time within 5000 ms. This method can be used in a lightweight IoT system.

Privacy Preserving File Auditing Schemes for Cloud Storage using Verifiable Random Function

Users leverage the cloud storage to store data by uploading files to the cloud storage. They can use it to share files to work on collaborative projects. However, during administrative operations by cloud storage service provider (CSSP), there may be some inadvertent corruption of files during data migration and backup. Due to heavy demands, the cloud service provider may not update the desired files immediately when requested by the owner. As a result, a user of the file may receive an obsolete file. To ensure integrity and freshness of files, third party auditing (TPA) services should be supported by CSSP while maintaining the confidentiality of user files and preserving privacy of users. In this paper, three privacy preserving auditing schemes for files stored in cloud has been proposed. Verifiable random function, merkle hash tree and ciphertext-policy attribute-based encryption has been used to achieve the desired goals.

A Novel Construction of Constrained Verifiable Random Functions

Constrained verifiable random functions (VRFs) were introduced by Fuchsbauer. In a constrained VRF, one can drive a constrained key skS from the master secret key sk, where S is a subset of the domain. Using the constrained key skS, one can compute function values at points which are not in the set S. The security of constrained VRFs requires that the VRFs’ output should be indistinguishable from a random value in the range. They showed how to construct constrained VRFs for the bit-fixing class and the circuit constrained class based on multilinear maps. Their construction can only achieve selective security where an attacker must declare which point he will attack at the beginning of experiment. In this work, we propose a novel construction for constrained verifiable random function from bilinear maps and prove that it satisfies a new security definition which is stronger than the selective security. We call it semiadaptive security where the attacker is allowed to make the evaluation queries before it outputs the challenge point. It can immediately get that if a scheme satisfied semiadaptive security, and it must satisfy selective security.

SKENO: Secret key encryption with non-interactive opening

Abstract In this paper, we introduce the notion of secret key encryption with non-interactive opening (SKENO). With SKENO, one can make a non-interactive proof π to show that the decryption result of a ciphertext C under a shared secret key K is indeed plaintext M without revealing K itself. SKENO is the secret key analogue of public key encryption with non-interactive opening (PKENO). We give a generic construction of SKENO from verifiable random function (VRF) with certain stronger uniqueness, for example, the Hohenberger–Waters VRF and the Berbain–Gilbert I V-dependent stream cipher construction. Although the strong primitive VRF is used, by taking advantage of the features of the stream cipher, we can still achieve good performance without sacrificing much of the efficiency. Though our VRF-based SKENO construction does not require random oracles, we show that SKENO can be constructed from weak VRF (which is strictly weaker primitive than VRF) in the random oracle model.

A Reputation System Preserving the Privacy of Feedback Providers and Resisting Sybil Attacks

Users hesitate to submit negative feedback in reputation systems due to the fear of retaliation from the recipient user. A Preserving reputation system which does not require continuous online communication with a trusted third party is proposed, Peers in this trust model use a verifiable random function, non-interactive zero-knowledge and ratee’s transaction identities, to generate evaluation tags, so as to anonymously evaluate the transaction objects and hide the identity of the transaction process. Analysis shows the scheme guarantees the privacy of feedback providers resists the inherent Sybil attacks in preserving reputation system and evidently improves the accuracy of trust accumulated value compared with existing trust models.

A secure and fair joint E-lottery protocol.

The attractive huge prize causes people to adore lotteries. Due to the very small probability of winning prizes, the players can enhance their probability of winning by using the method of joint purchase. In spite of many lottery schemes having been proposed, most e-lottery schemes focus on the players' privacy or computation overhead rather than support a joint purchase protocol on the Internet. In this paper, we use the multisignature and verifiable random function to construct a secure and fair joint e-lottery scheme. The players can check the lottery integrity, and the winning numbers can be verified publicly.