Sybil attack meaning is a kind of security threat on an online system where one person attempts to take over the network by creating multiple accounts, nodes or computers. In the crypto space, this happens when someone runs multiple nodes on a blockchain network in a bid to take over the platform.
The word “Sybil” in the name originated from a case study about a woman named Sybil Dorsett, who was treated for Dissociative Identity Disorder, also known as Multiple Personality Disorder.
Why are the effects of Sybil attacks?
Attackers may be able to out-vote the honest nodes on the network if they can create enough fake identities (or Sybil identities). They can then refuse to receive or transmit blocks, effectively blocking other users from a network.
In extremely large-scale Sybil attacks, where the attackers manage to control the majority of the network computing power or hash rate, they can carry out a 51% attack. Attackers may change the ordering of transactions, and prevent transactions from being confirmed. They may even reverse transactions that they made while in control, which can lead to double spending, benefiting themselves.
As of right now, despite all the efforts from computer scientists to figure out how to detect and prevent Sybil attacks, there is no guaranteed defence against the attack.
How to mitigate Sybil attacks?
Many blockchains use different “consensus algorithms” to help defend against Sybil attacks, such as Proof of Work, Proof of Stake, and Delegated Proof of Stake. Although these consensus algorithms do not defend against a Sybil attack completely, they make it impractical for a Sybil attack to happen.
For instance, Bitcoin’s blockchain applies a specific set of rules to the generation of new blocks.
One of the rules is that the ability to create a block must be proportional to the total processing power of the Proof of Work mechanism. That means that you have to actually own the computer power required to create a new block, which makes it very difficult and costly for an attacker to do.
Since mining Bitcoin is so intensive, miners have a very strong incentive to keep mining honestly, instead of attempting a Sybil attack.
In Conclusion
Sybil attack meaning is a kind of security threat that happens when one person, or a group of people, try to take over the network by creating multiple accounts. Blockchain systems try to mitigate this by making controlling the network very costly and impractical.
