1. Double Spending Attack
A double spending attack, as the name suggests, is an attack where a malicious actor tries to spend the same coin twice. This attack is mitigated by the Bitcoin network’s consensus mechanisms. When a bitcoin transaction is made, the transaction is broadcasted to all the nodes in the network. All these nodes check the validity of the transaction and if the transaction is valid, it is added to the block chain. Once the transaction is added to the block chain, it is immutable and cannot be changed or reversed.
2. Sybil Attack
A Sybil attack is an attack where a malicious actor creates multiple identities on the network by creating multiple nodes. This attack is mitigated by the Bitcoin network’s proof-of-work consensus mechanism. When a new node is added to the network, it is required to perform a certain amount of computation before it can be added to the network. This computation is referred to as proof-of-work and this makes it difficult for malicious actors to create multiple nodes on the network.
3. 51% Attack
A 51% attack is an attack where a malicious actor controls more than 51% of the network’s computing power. This attack is mitigated by the Bitcoin network’s decentralized nature. As the network is decentralized, it is very difficult for a malicious actor to control more than 51% of the network’s computing power.
4. Transaction Malleability Attack
A transaction malleability attack is an attack where a malicious actor can modify a transaction without changing the transaction’s input or output. This attack is mitigated by the Bitcoin network’s signature scheme. The signature scheme ensures that each transaction is cryptographically signed, making it very difficult for a malicious actor to modify a transaction without changing the transaction’s input or output.