Survey on Security Mechanisms against the 51% vulnerability attack in Blockchain (original) (raw)

When a miner or a group of miners attempt to control more than 50% of a network's mining power, computing power or hash rate, it is called 51% attack. The attackers can block new transactions from taking place or being confirmed. This attack was considered very unlikely for a long period due to the immense attacking cost. However, the attack has befallen at a frequent pace in recent times. These attackers can double-spend the same cryptocoin, restrict transactions, cancel blocks, and even have full control over the value of a cryptocurrency. In this paper, we tend to discuss the protection techniques to prevent this attack and we will have a security-based analysis on each technique.