## Introduction
Vector76 is a sophisticated attack on blockchain systems that combines elements of the Race and Finney attacks. This attack aims to manipulate transactions and blocks for financial gain by the attacker. In this article we will look at the mechanism of the Vector76 attack, its consequences and recommendations for protection against such threats.
## Vector76 Attack Mechanism
### Step 1: Creating Nodes
The attacker creates two nodes in the blockchain network:
1. Node A, which is connected only to the exchange node.
2. Node B, which is connected to well-connected nodes in the blockchain network.
### Step 2: Create Transactions
An attacker-controlled miner creates two transactions:
– Transaction X with a high value.
– Transaction Y with low value.
### Step 3: Pre-Mine and Block Hold
The attacker pre-mines a block containing transaction X and keeps it from being distributed throughout the network. This block is not visible to the main part of the network, but is ready for rapid distribution.
### Step 4: Block Declaration
Once a block is declared, the attacker quickly sends a pre-mined block with transaction X directly to the exchange node. The exchange node and some miners begin to consider this block as the main chain and confirm transaction X.
### Step 5: Submit Transaction Y
After transaction X is confirmed by the exchange service, the attacker sends transaction Y to the main network. As a result, the network rejects transaction X because it is not part of the main chain.
### Summary
The attacker’s account is credited with transaction amount X, even though the main network rejected it. Thus, the attacker gains financial benefit by manipulating blocks and transactions.
## Attack Success Probability:
Although the success rate of a Vector76 attack is very high and occurs very often. This is due to the fact that its implementation requires:
– A hosted cold wallet that accepts payment after one confirmation.
– Node with an incoming transaction.
## Defense Recommendations
To protect against Vector76 attacks, it is recommended to:
– Complete payments only after the transaction has been confirmed by a sufficient number of blocks (at least six).
– Use additional mechanisms for checking and validating transactions.
## Conclusion
The Vector76 attack poses a serious threat to blockchain systems, especially those that accept payments after a single confirmation. Understanding the mechanism of this attack and implementing appropriate security measures will help minimize risks and ensure the security of transactions on the blockchain.
## Links
– Vector name on the blockchain: Blockchain Attack Vectors: Main Vulnerabilities of Blockchain Technology
