A Sybil attack in blockchain is when a single attacker creates numerous fake identities (nodes/accounts) to gain disproportionate influence, overwhelming the network's integrity
often to manipulate transactions, censor others, or launch further scams, making it seem like many users support malicious actions, despite originating from one source. Because blockchain is a peer-to-peer network with pseudo-anonymous users, it's vulnerable to this, allowing attackers to trick honest participants into trusting their fake personas.
How it works
- Identity Creation: An attacker creates many fake digital identities (Sybil identities) on the network.
- Network Manipulation: These fake identities act as independent nodes, tricking the system and other users into perceiving them as legitimate, separate entities.
- Gaining Influence: By controlling many identities, the attacker gains majority control or influence, allowing them to control transaction flow or sow distrust.
Goals of a Sybil attack
- Manipulate consensus: Overwhelm voting or validation processes.
- Censor transactions: Block legitimate users from participating.
- Spreading misinformation: Create false narratives or pump/dump tokens.
- Launch other attacks: Isolate a target node or facilitate phishing.
Example
Imagine a decentralized voting system on a blockchain; an attacker creates 100 fake accounts (Sybil identities) to cast votes, making it appear that 100 people support a malicious proposal, even if only one person controls them all.
Prevention methods
- Identity Validation: Requiring proof of unique real-world identity.
- Economic Costs: Making it expensive to create identities (e.g., requiring staking).
- Social Trust Graphs: Analyzing connections to detect non-organic clusters of identities.
