#### Introduction
Race Attack is one of the most common threats in blockchain systems. It is carried out by an attacker who creates two conflicting transactions in order to deceive the recipient. In this article we will look at the mechanism of a racing attack, its consequences and ways to protect against it.
#### Racing attack mechanism
A racing attack begins with the attacker creating two transactions:
1. The first transaction is sent to the victim. The victim, without waiting for the transaction confirmation, accepts the payment and, for example, sends the goods.
2. The second transaction is broadcast to the network and returns the same amount of cryptocurrency to the attacker as in the first transaction.
Since the blockchain network operates on a consensus basis, only one of these transactions can be confirmed and included in a block. If the second transaction is confirmed before the first, then the first transaction becomes invalid. As a result, the victim loses the product or service without receiving payment for it.
#### Example of a racing attack
Let’s look at an example. An attacker buys a product from an online store, paying with cryptocurrency. He sends the first transaction to the store, which immediately ships the product without waiting for confirmation. At the same time, the attacker sends a second transaction, which returns the same amount of cryptocurrency to him. If the second transaction is confirmed earlier, the store remains without payment.
#### Security recommendations
To protect against racing attacks, the following is recommended:
1. Wait for the transaction to be confirmed: The exchange or recipient must complete the payment only after the transaction has been confirmed by a sufficient number of blocks. It is generally recommended to wait for 6 confirmations to minimize the risk of an attack.
2. Using secure wallets: Using wallets that have a conflicting transaction tracking feature can help detect a racing attack in time.
3. Strengthen controls: Implementing additional security measures, such as two-factor authentication and monitoring for suspicious activity, can reduce the risk of attacks.
#### Conclusion
A racing attack poses a serious threat to participants in blockchain systems. However, following security best practices and using modern technology can significantly reduce the risk of such attacks. It is important to remember that in blockchain systems, the security of transactions depends on the care and awareness of all participants.
For a more detailed study of attack vectors on blockchain systems, we recommend that you read the materials at the link: attack vectors on blockchain .
