An unknown perpetrator initiated the famous Sybil attack (in conjunction with the traffic verification attack) on the anonymous Tor network over a few months in mid-2014, which was first recognized in January 2014. In recent years, the cryptocurrency world has seen its fair share of high-profile attacks on various Blockchains and projects.
Cyber attacks such as 51 percent attacks and hard fork attacks are well-known in the crypto world. This blog post looks at the Sybil Attack, highlighting its meaning, mode of operation, and how to avoid it.
Table of Contents
What is a Sybil Attack?
A Sybil attack is an attack that endangers system security because it is carried out by a malicious actor who attempts to fully control a network by using multiple fake ids, nodes, or computers.
This type of attack is most common in p2p (peer-to-peer) networks, which are networks that operate through a network of nodes or computers that operate in the same way as each other.
The network’s susceptibility to Sybil attacks is determined by how low the cost of creating an account is, the extent to which the system accepts input from organizations that are not linked to the chain of trusted devices, and whether the network is correct in treating all entities equally.
The term “Sybil” came from a book about a woman diagnosed with a dissociative identity disorder. Sybil attacks are also referred to as sockpuppetry.
Sybil Attack Mode of Operation
Sybil attacks on the blockchain network can result in false resource sharing, a lack of redundancy, decreased reliability, and a lack of credibility.
Peer-to-peer networks use several identities for redundancy, sharing resources, durability, and integrity.
In order to be considered and function as multiple different nodes on the peer-to-peer network, the attacker can present different identities to the network. As a result, unfavorable factors can gain excessive control over the network, such as by influencing voting outcomes.
When an attacker gains control of the majority of the network’s computational power or hash rate. He may decide to change the order of transactions, preventing them from being confirmed. The attacker may also change transactions made while in control, resulting in double-spending.
How does the Bitcoin network protect against Sybil attacks?
To validate the authenticity of any block added to the blockchain, the Bitcoin network utilizes the Proof of Work (PoW) consensus algorithm. A significant amount of computing power is required to complete the work, which incentivizes miners to do honest work (a bitcoin reward; presently 12.5 bitcoins for every block mined) while providing no incentive for faulty work. Every node verifies the transactions and rejects them as invalid if they are included in the block. A type of Sybil attack known as the 51 percent attack is also nearly impossible in the bitcoin network due to a large number of miners; it is extremely difficult for a single company to control 51 percent of the miners.
How does Blockchain help in Preventing Sybil Attack?
Identity Verification
Identity-based verification technology solutions frequently provide accountability at the expense of confidentiality, which can be an unfavorable compromise, particularly in online forums where censorship-free sharing information and open discussion of sensitive issues are desired. Although verification authorities can attempt to protect user privacy by denying reverse lookups, this approach makes confirmation authorities the primary target of attacks.
Economic cost
Economic costs can be imposed as an artificial entry barrier to make Sybil attacks more costly. A proof of work, for example, requires users to demonstrate that they expended a certain amount of computing power effort solving password problems. This facilitates the defense against its attack.
For generating new blocks, Bitcoin’s blockchain follows a set of rules. One of the rules requires that the ability to create blocks be directly proportionate to the overall processing capacity of the proof-of-work method. This means that you genuinely need computing power to make a new block, which makes it difficult and expensive for an attacker to do.
Because Bitcoin mining is so severe, miners have a strong incentive to continue mining honestly rather than attempting Sybil attacks.
Use of Sybil-Specific Application
Many applications have been created to protect against Sybil attacks. Whnau, I2P’s application of Kademlia SumUp, and DSybil are a few examples.
How Sybil Attack Can Be Prevented?
There are five important methods to take to reduce the risk of such attacks:
Different members should be given different powers.
One solution could be reputation systems, in which different levels of power are assigned to people based on their reliability within the network.
Create costs in order to create an identity.
An amount of money may be requested in order for each individual to create an identity. As a result, it will be more difficult for the attacker to cover the costs of carrying out his attack.
Keep the number of identities per node to a minimum.
One effective method is to prevent multiple fake identities from operating from the same IP or device at the same time.
Verify identities before connecting to the network.
There are two approaches to this:
The direct method, in which a founded entity is in charge of verifying the new network member.
The indirect one, on the other hand, functions as a trust system in which the founded entity verifies some members.
Then there’s the question of who can verify the new members who participate after them, and so on. This model presumes that new users are truthful.
For the creation of new blocks, follow a set of rules.
Different projects’ consensus algorithms, such as Bitcoin’s, use “rules” to avoid these attacks. One of them could be that each node possesses the computational power required to create a new block.
As a result, it will be difficult to create multiple identities that do not originate from the same PC, especially when algorithms like Proof of Work are used. Similarly, through rewards, they ensure that miners maintain the integrity of their mining.
Conclusion
Despite the fact that there are no foolproof defense mechanisms against Sybil attacks, the number of Sybil attacks on the blockchain has decreased significantly over the years.
