# A Survey on Consensus Protocols and Attacks on Blockchain Technology
## 1 Introduction
\begin{table}
\begin{tabular}{c c c} \hline
**Authors** & **Attack** & **Description** \\
**Year** & & Crypto-jacking is the unlawful mining of cryptocurrencies on someone else’s computer. Hackers achieve this by infecting an online ad or website with program code that auto-executes by convincing the victim to click on a malicious link in an email that installs crypto-mining code on the computer. \\ \hline \multirow{5}{*}{[PERSON]. [PERSON], et al. 2018 [48]} & \multirow{5}{*}{Crypto-jacking attack} & \multirow{5}{*}{The term “double spending” refers to the same transaction twice or more.} \\ \cline{3-3}  & & When a node first connects to a network, it counts a DNS server to see which nobles are currently available. A hacker could poison the DNS server at the resolver or introduce an erroneous list of speeder nodes before that time. As a result, the node will believe it is connected to the genuine Bitcoin network when, in fact, it is connected to the attackers. \\ \cline{3-3}  & & DDoS attacks are a type of DoS attack. A DDoS attack entails a network of connected online devices, known as a botnet, that are used to flood a target website with bogus traffic. DDoS attacks, unlike other types of cyberattacks, do not attempt to breach your security perimeter. A DDoS attack, on the other hand, seeks to make your website and servers unavailable to legitimate users. \\ \hline \multirow{5}{*}{[PERSON] et al. 2018 [50]} & \multirow{5}{*}{Eclipse} & When an eclipse attack is carried out, the attacker attempts to redirect the target user’s outbound and inbound connections away from genuine nearby nodes and toward attacker-controlled nodes, effectively isolating the target from the rest of the network. \\ \cline{3-3}  & & The eclipse attack hides the true ledger state from a single node, whereas the Sybil attacks the entire network. With a number of alienated nodes, the attacker will overwhelm the network. Alternatively, they can slag to get relay blocks, essentially barring other network users, or they can allow a 51 percent or double-spending assault to take place. \\ \hline \multirow{5}{*}{[PERSON]. [PERSON], [PERSON] et al. 2021 [52]} & \multirow{5}{*}{Time-jacking} & The eclipse attack hides the true ledger state from a single node, whereas the Sybil attacks the entire network. With a number of alienated nodes, the attacker will overwhelm the network. Alternatively, they can slag to get relay blocks, essentially barring other network users, or they can allow a 51 percent or double-spending assault to take place. \\ \cline{3-3}  & & Nodes on the crypto coin preserve an inner counter that indicates network time. The node gains the network time by entreating it from neighbouring nodes during the bootstrapping phase, calculates and stores the median, and so on. The system time will be used if the median is greater than 70 min. An eclipse attack, for example, would be used in an attack to allow neighbouring nodes to supply false timestamps. \\ \cline{3-3}  & & Selfish mining is a shady cryptocurrency mining approach in which a single miner or a group solves a hash, creates a new block, and keeps it off the public blockchain. This step generates a fork, which is then mined to gain an advantage over the public blockchain. The group’s blockchain can introduce its newest block to the network if it gets ahead of the honest blockchain. As the network is set up to recognize the most recent block, the fork by the group would erase the original blockchain. By modifying the blockchain, miners might effectively steal money from other users. \\ \hline \multirow{5}{*}{Eyal 2018 [54]} & \multirow{5}{*}{Fork after withholding} & The following is how the FAW attack is carried out. Infiltration mining occurs when a miner enters a selected pool while remaining a miner in their preferred pool. If they mine a block using FPoW at their preferred pool, they immediately submit it and earn legitimate profit as pool manager. \\ \cline{3-3}  & & The following is how the FAW attack is carried out. Infiltration mining occurs when a miner enters a selected pool while remaining a miner in their preferred pool. If they mine a block using FPoW at their preferred pool, they immediately submit it and earn legitimate profit as pool manager. \\ \cline{3-3}  & & The following is how the FAW attack is carried out. Infiltration mining occurs when a miner enters a selected pool while remaining a miner in their preferred pool. If they mine a block using FPoW at their preferred pool, they immediately submit it and earn legitimate profit as pool manager. \\ \hline \end{tabular}
\end{table}