Summary # Vertcoin, a cryptocurrency that focuses on decentralization, was hit by a 51% attack in October 2018. The attack led to double-spending and the loss of thousands of dollars in assets. The attackers took advantage of the Lyra2REv2 algorithm, which was susceptible to NiceHash-driven attacks due to the availability of hash power for rent. In response to the attack, Vertcoin switched to a new algorithm called Verthash, which aimed to provide better security against similar attacks in the future.
...
Summary # On June 2, 2018, ZenCash, now known as Horizen (ZEN), fell victim to a 51% attack. During this attack, the perpetrator managed to double-spend ZEN coins by gaining control of a majority of the network’s hashrate. The attack lasted several hours and resulted in an estimated loss of approximately 23,000 ZEN, which was equivalent to about $550,000 at that time.
Attackers # The identity of the attacker or attackers who conducted the 51% attack on the ZenCash network remains unknown.
...
Summary # Bitcoin Gold was hit by a 51% attack on May 19, 2018. The attackers were able to double-spend 388,000 BTG, worth around $18 million at the time of the attack. Affected exchanges included Bitinka, Bithumb, Coinnest, Bittrex, and Bitfinex, while wallets such as the official Bitcoin Gold wallet and Ledger wallet were also impacted. As a result of the attack, Bitcoin Gold’s value dropped from around $60 to $30 per coin.
...
Summary # Verge blockchain fell victim to a hybrid attack, which combined a mining algorithm exploit with a 51% attack. Attackers exploited vulnerabilities in Verge’s mining algorithm and a bug in the retargeting mechanism, allowing them to mine blocks rapidly and accumulate approximately 250,000 XVG coins, worth $1.75 million. The attack began on April 4, 2018, and despite the Verge development team’s attempts to release patches, the issue persisted until April 9, 2018, when a second patch finally resolved the problem.
...
Summary # Shift, a blockchain project focused on decentralized web hosting, was hit by a 51% attack in late August 2016. The attackers were able to take control of more than half of the network’s mining power, enabling them to reorganize the blockchain and carry out double-spending attacks.
Attackers # The identities of the attackers remain unknown.
Losses # The exact amount of losses in the Shift 51% attack is not clear.
...
Summary # Krypton, an Ethereum-based blockchain, experienced a 51% attack in August 2016. The attackers were able to control more than half of the network’s hash rate, enabling them to manipulate the blockchain and double-spend KR tokens.
Attackers # The identity of the attackers remains unknown.
Losses # It was reported that the attackers managed to steal approximately 21,465 KR tokens, which had a value of about $3,000 at the time of the attack.
...
Summary # In May 2013, Feathercoin was attacked by a 51% attack that resulted in the loss of millions of dollars. The attack was carried out by an attacker who was able to gain control of more than 51% of the network’s computing power. The attack lasted for several days, during which the attacker was able to reverse transactions that had been completed while they were in control. The attacker was able to reverse transactions and double-spend coins, resulting in a significant loss for Feathercoin users.
...