A p/2p/2 Adversary Power Resistant Blockchain Sharding Approach

Blockchain Sharding is a blockchain performance enhancement approach. By splitting a blockchain into several parallel-run committees (shards), it helps increase transaction throughput, reduce computational resources required, and increase reward expectation for participants. Recently, several flexible sharding methods that can tolerate up to $n/2$ Byzantine nodes ($n/2$ security level) have been proposed. However, these methods suffer from three main drawbacks. First, in a non-sharding blockchain, nodes can have different weight (power or stake) to create a consensus, and as such an adversary needs to control half of the overall weight in order to manipulate the system ($p/2$ security level). In blockchain sharding, all nodes carry the same weight. Thus, it is only under the assumption that honest participants create as many nodes as they should that a $n/2$ security level blockchain sharding reaches the $p/2$ security level. Second, when some nodes leave the system, other nodes need to be reassigned, frequently, from shard to shard in order to maintain the security level. This has an adverse effect on system performance. Third, while some $n/2$ approaches can maintain data integrity with up to $n/2$ Byzantine nodes, their systems can halt with a smaller number of Byzantine nodes. In this paper, we present a $p/2$ security level blockchain sharding approach that does not require honest participants to create multiple nodes, requires less node reassignment when some nodes leave the system, and can prevent the system from halting. Our experiments show that our new approach outperforms existing blockchain sharding approaches in terms of security, transaction throughput and flexibility

Design and development of a parallel Proof of Work for permissionless blockchain systems

Blockchain, which is the underlying technology for the Bitcoin cryptocurrency, is a distributed ledger forming a decentralized consensus in a peer-to-peer network. A large number of the current cryptocurrencies use blockchain technology to maintain the network and the peers use a consensus mechanism called Proof of Work to verify and confirm the transactions. However, the transaction speed in this process is significantly slower than traditional digital transaction systems such as credit cards or PayPal. In this thesis, a parallel Proof of Work model is proposed in order to increase the scalability of the processing of the transactions. The goal of this model is to ensure that, no two or more miners put the same effort into solving the same block. This model differs from traditional Proof of Work or the Bitcoin pool mining in many aspects, such as the responsibilities of the manager, contribution of active miners, and the reward system. A proof of concept prototype of the proposed model has been constructed based on the attributes of Bitcoin. The prototype has been tested in a local as well as in a cloud environment and results show the feasibility of the proposed model

SoK: Diving into DAG-based Blockchain Systems

Blockchain plays an important role in cryptocurrency markets and technology services. However, limitations on high latency and low scalability retard their adoptions and applications in classic designs. Reconstructed blockchain systems have been proposed to avoid the consumption of competitive transactions caused by linear sequenced blocks. These systems, instead, structure transactions/blocks in the form of Directed Acyclic Graph (DAG) and consequently re-build upper layer components including consensus, incentives, \textit{etc.} The promise of DAG-based blockchain systems is to enable fast confirmation (complete transactions within million seconds) and high scalability (attach transactions in parallel) without significantly compromising security. However, this field still lacks systematic work that summarises the DAG technique. To bridge the gap, this Systematization of Knowledge (SoK) provides a comprehensive analysis of DAG-based blockchain systems. Through deconstructing open-sourced systems and reviewing academic researches, we conclude the main components and featured properties of systems, and provide the approach to establish a DAG. With this in hand, we analyze the security and performance of several leading systems, followed by discussions and comparisons with concurrent (scaling blockchain) techniques. We further identify open challenges to highlight the potentiality of DAG-based solutions and indicate their promising directions for future research.Comment: Full versio

How to break IOTA heart by replaying?

IOTA is a novel cryptocurrency that uses distributed ledger technology based on directed acyclic graph data structure. Security of cryptocurrencies ought to be scrutinized in order to acquire esteemed security, attain trust, and accomplish indelible adoption. Although IOTA proffer resilient security controls, IOTA security is not yet well explored. Among all the propounded IOTA vulnerabilities that have been identified, we pragmatically exploit replay attack against IOTA. We further analyze the attack to perceive its impact. Attack methodology and proof of concept for the replay attack is presented. Our proposed exploitation methodology is based upon address reuse, while IOTA in default mode does not reuse addresses. Distrust, and privation of balance can be some of the severe impacts of this vulnerability

Novel artificial intelligence method for decision chain within blockchain technology

The objective of the distributed system is to distribute the resources and the calculations. Blockchain is the art of interconnecting data into a tamper-proof and tamper-resistant ledger. Security is ensured by making the cost of malicious activities very high, trans- parency is inherited from a high level of duplication, and privacy is the result of using cryptography. Consensus is at the heart of the technology to orchestrate nodes to provide finality. However, it has a disadvantage because it bases the decision on different means, which are votes, stake or resources. The decision makes the system prone to monopoly or inconsistencies. In addition, the system suffers from a high validation lag compared to centralized systems. Thus, the injection of a novel artificial intelligence method that can learn and automate the space of actions allow the technology to respond to criticisms of efficiency. This work introduces a new approach in the maintenance of distributed ledger. It will start with the introduction of TheChain as a platform, which is based on the concept of node independence as incentive for competency. Second, TheCoin is the data that will be exchanged between different nodes, which is flexibly modeled to hold different types of symbolic elements. Finally, TheTree is a sociology-inspired approach to maintain va- lidity. It introduced the concept model as a distributed modeling approach and changed decision and security from a component to a network. At TheChain level, monopoly as a philosophical issue was addressed, a conceptual comparison was demonstrated, a se- curity discussion and an operation scenario were investigated. At TheCoin level, discus- sion of security, conceptual comparison, system size and performance are demonstrated. TheTree section will provide a safety discussion, formal study, environment modelisation and conceptual comparisons. The contribution is to provide a non-monopoly-prone plat- form built on a new philosophical principle to solve security problems. Second, TheCoin reduce the size of the block and retain the use of coins to offer parallel transaction pro- cessing, in which it has been reported that TheCoin can be with 10% of normal block size in case of micropayment. TheTree defined a new approach to dealing with malicious users by leveraging regional consistency. The propagation and consistency times are faster than any previous work. Moreover, the cost of malicious activities has been shown to be very high