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Blockchain User, Network and System-Level Attacks and Mitigation
Published in Shaun Aghili, The Auditor's Guide to Blockchain Technology, 2023
Nishtha Baria, Dharmil Parmar, Vidhi Panchal
In this type of attack, there is a group of miners that attain the majority of the network’s hash rate. This hash rate refers to the measuring unit of the processing power of a blockchain network which in turn may enable blockchain manipulations, such as the ability to stop transactions from being checked, thus making them invalid. Using this attack mode, a detached chain is introduced to the network, thereby making it appear as a legitimate chain. The double-spending attack is enabled at this stage. Double spending refers to an instance where the malicious user sends the copy of a transaction to make it look legitimate in order to enable a digital token to be spent more than once. As previously mentioned, in blockchain policy, the longest chain rule is applied. If the malicious users have more than 50% of the total hashing power in the network, the malicious users would be able to operate the longest chain in the blockchain network which is the required proportion for a 51% attack [30].
Bitcoin
Published in Sandeep Kumar Panda, Ahmed A. Elngar, Valentina Emilia Balas, Mohammed Kayed, Bitcoin and Blockchain, 2020
Double spending is a situation where a fraudulent user tries to spend the same set of coins in two different transactions simultaneously. For example, a malicious user creates a transact T at time t using a set of Bitcoins Bc to a vender V to purchase something. At the same time, the user creates and broadcasts another transactions T′ using the same coins Bc, and sends the coins to his wallet address. This situation is called “double spending,” where V will accept the purchase and send the goods, but cannot redeem the coins. For the coins are transmitted to the user’s account. This problem can be solved by enforcing the rule by the network miners who will validate and process the transactions to ensure that coins spent in previous transactions are not used as inputs for the subsequent transaction. Also, the PoW bases consensus and time-stamping helps in the orderly storage of transactions in blockchain. In this case, when a miner receives T and T′ transactions, it can check if both transactions seek to use the same coins, and thus process only one transaction and reject the other. Figure 1.5 shows the double spending attack.
Hardware-primitive-based blockchain for IoT in fog and edge computing
Published in Muhammad Maaz Rehan, Mubashir Husain Rehmani, Blockchain-enabled Fog and Edge Computing, 2020
Uzair Javaid, Muhammad Naveed Aman, Biplab Sikdar
Blockchain operates in a peer-to-peer (P2P) fashion (i.e., it depends on its network constituents for its resources and computation). There is no central authority here, but a collective mechanism is employed over its constituents: The nodes. This is so that system nodes can work together and secure the blockchain from adversaries. Although double spending has been a problem for a long time in both centralised and decentralised payment protocols, the blockchain makes it infeasible unless and until an adversary or a group of adversaries gain control of 51% computational power of the network [9].
On the Security Risks of the Blockchain
Published in Journal of Computer Information Systems, 2020
Efpraxia Zamani, Ying He, Matthew Phillips
The strength of the Bitcoin protocol is that it is open source, and publicly available to everyone, meaning that everybody can examine the code. However, this is a double-edged sword: upon identifying a weakness in the code, one may alter the network, but equally, may be less benevolent and choose to exploit the unknown security vulnerabilities through a zero-day attack.27 Another threat is that of time jacking attacks.28 Time jacking is initiated when an attacker announces an inaccurate timestamp for a block. As the attacker is connected to other nodes, they may accept this inaccurately timestamped block, and as a result the network time counter speeds up for the majority of the miners. In essence, there will be a fork created for the blockchain, with miners adding new blocks in a longer chain which has been tampered with. The consequence is that there are opportunities for double-spending, i.e., the same cryptocurrencies spent more than once. In addition, it would lead to wasting valuable computational resources during mining, as benevolent miners will be mining for the counterfeit chain.15
CKshare: secured cloud-based knowledge-sharing blockchain for injection mold redesign
Published in Enterprise Information Systems, 2019
Zhi Li, Xinlai Liu, W. M. Wang, Ali Vatankhah Barenji, George Q. Huang
In this section, we will elaborate on the creation of the TBC for a knowledge block based on the bitcoin. As such, the TBC is a distributed ledger on a P2P network, which is open and public to the members; however, it can only be secured though the power of cryptography. Moreover, for improving the TBC, there are still three distinguished differences between bitcoins and transactions. Ownership. In the case of bitcoins, the ownership of the digital currency flows with the transfer. However, in the proposed TBC, the ownership cannot change the sharing or transaction behaviors.Content. Bitcoin transactions will hide personal information from the two parties rather than the content of the transaction. On the proposed platform, however, the content of the knowledge in the sharing process needs to be encrypted and the information of the receivers and senders needs to be verified through membership protocols.Double-spending problem. The bitcoin has solved the ‘double-spending’ problem perfectly. But there is no double-spending problem in the knowledge transaction process.
A blockchain-based transaction system with payment statistics and supervision
Published in Connection Science, 2022
Liutao Zhao, Jiawan Zhang, Lin Zhong
Bitcoin (Nakamoto, 2019) is a peer-to-peer electronic cash that enables internet operations would be sent immediately between parties without the need of a bureaucratic commercial bank. By using the proof-of-work consensus mechanism and network timestamps, it prevents double-spending without using a trusted third party. Etherum (Wood, 2014) has demonstrated its strong practicality through a larger quantity of work. Each work can be seen as a simple application on a decentralised, but singleton, compute resource. However, Bitcoin and Ethereum use plaintext to transact, which reveal the private information of each user and lead hackers to conduct statistical analysis attacks on it.