Payment guarantee smart contract in Ethereum: security and transparency in transactions + sample codes

In the digital age, making safe and reliable transactions is very important. Due to the growth of electronic markets and online payments, the need for methods to ensure the security and reliability of two-way transactions has increased. In this context, block chain technology and smart contract using Solidity programming language to create contracts that automatically execute transactions and have high security have been considered. Payment guarantee smart contract in Ethereum is a safe and secure solution for conducting digital transactions between two different parties. With this smart contract, transaction security increases and problems such as fraud, forgery, and buyer dissatisfaction with the product are reduced. Also, the use of smart contracts in online markets and digital currency transactions increases the speed and efficiency of transactions. Due to the fact that it can be implemented in the Ethereum blockchain, it can also be used in freelance projects. In this article, I will introduce the smart contract of the guarantee of payment obligation in the blockchain, which is written in the Solidity language on the Ethereum platform. I will also examine how payment obligation guarantees work in blockchain using smart contracts. This smart contract is designed for two-way transactions using Ethereum blockchain and makes two-way payments with payment guarantee. Through this smart contract, the seller can avoid the risks of non-payment or fraudulent transactions, and conversely, the buyer can be sure that his payments will be sent to the seller correctly. The structure of the smart contract of the payment obligation guarantee in the blockchain:

In this smart contract, several variables are used:

pragma solidity >=0.4.22 <0.9.0;

Contract Payment Guarantee

address payable public seller; // address of the seller

address payable public buyer; // Buyer's address

public uint price; // The price of the product

uint public deposit; // Advance payment

public bool paid; // Payment status

constructor(address payable \_seller, uint \_price, uint \_deposit) public {

seller = \_seller;

buyer = msg.sender;

price = \_price;

deposit = \_deposit;

paid = false;

}

function confirm() public payable {

require(msg.sender == buyer, "Only buyer can confirm the transaction.");

require(msg.value == deposit, "Deposit amount should be equal to the agreed amount.");

paid = true;

}

function finalize() public {

require(msg.sender == buyer || msg.sender == seller, "Only buyer or seller can finalize the transaction.");

require(paid == true, "Payment should be confirmed first.");

seller.transfer(price);

selfdestruct(buyer);

}

}

Variables:

address payable public seller;

address payable public buyer;

public uint price;

uint public deposit;

public bool paid;

seller: a variable of the address payable type that stores the address of the seller. buyer: a variable of the address payable type that stores the address of the buyer. price: a variable of type uint that stores the price of the product. deposit: a uint type variable that stores the amount of advance payment. paid: a bool type variable that indicates whether the advance payment has been paid or not.

constructor function:

constructor(address payable \_seller, uint \_price, uint \_deposit) public {

seller = \_seller;

buyer = msg.sender;

price = \_price;

deposit = \_deposit;

paid = false;

}

This function is executed when creating a contract and sets the seller's address, price and advance payment. At the beginning of the contract, the constructor function is defined, which takes the parameters of seller, price and deposit as input and values ​​the related variables through this. Also, the buyer's address is determined using msg.sender in this function.

confirm function:

function confirm() public payable {

require(msg.sender == buyer, "Only buyer can confirm the transaction.");

require(msg.value == deposit, "Deposit amount should be equal to the agreed amount.");

paid = true;

}

This function can only be called by the buyer. The buyer must send exactly the specified down payment amount. If the conditions are met, the payment status will change to true.

finalize function:

function finalize() public {

require(msg.sender == buyer || msg.sender == seller, "Only buyer or seller can finalize the transaction.");

require(paid == true, "Payment should be confirmed first.");

seller.transfer(price);

selfdestruct(buyer);

}

Only buyer or seller can call this function. If the advance payment is approved, the amount of the goods will be transferred to the seller. Then the contract is completely destroyed and the resources are transferred to the buyer's address.

Important points of the smart contract:

This contract is completely destroyed using the selfdestruct method and all its balances are transferred to the buyer. All transactions and statuses are recorded and provide complete transparency in the buying and selling process.

summary of the smart contract:

The PaymentGuarantee contract provides a safe and transparent way to guarantee payments between the buyer and the seller, which includes advance payment and payment confirmation.

How ​​smart contract works:

The smart contract is the guarantee of the payment obligation in the blockchain, including both the seller and the buyer. To create a transaction using this smart contract, the buyer must pay the amount that is supposed to be paid for the product, and this amount is automatically stored in the smart contract. Then, the seller must ship the product to the buyer. If the buyer receives the product and is satisfied with it, he must confirm that the product has been received correctly and as intended. After the buyer's approval, the amount stored in the smart contract will be paid to the seller. If the buyer received the product but was not satisfied with it and expressed his dissatisfaction with the product, the seller can fix this problem and take the product back. In this case, the amount saved in the smart contract will be returned to the buyer. If the buyer does not receive the product for any reason, after the specified time, the amount stored in the smart contract will be transferred to the seller.

will be paid

Ensure security:

The payment guarantee smart contract has high security. Due to the use of the Ethereum blockchain, the transactions performed prevent any fraud and forgery of digital currencies. Also, with this smart contract, both parties are sure that the amount paid will be saved and paid automatically.

How ​​to use smart contract:

The payment guarantee smart contract can be used in many fields. For example, this smart contract can be used in online markets to sell various products, among digital buyers and sellers, in doing freelance projects and even in digital currency transactions. To use the "guarantee of payment" smart contract, it is enough for the seller and the buyer to coordinate and execute this smart contract in the Ethereum blockchain. To use the guarantee smart contract in your transactions, you must first compile a program written in the Solidity language in Ethereum and then publish it to the Ethereum network. After the contract is published, anyone who wants to make a transaction with you can make the payment safely and securely by executing the smart contract. To make a transaction, the buyer must put some of his ethers in the smart contract address in advance. If the purchase conditions are met by the seller, the desired amount to H

The sub-seller will be transferred and otherwise, the ether placed by the buyer will be returned to his account. Also, in this smart contract, the terms and conditions that must be met to complete the desired transaction are determined by the seller. For example, for the purchase of goods, the conditions related to the type of goods, price, quantity and other items can be specified in the smart contract.

Function of smart contract:

The task of the smart contract is to guarantee payment, check and verify the validity of transactions. To do this, the smart contract receives the transaction amount and transfers the amount to the seller after the approval of the transaction parties. If the buyer is not satisfied with the goods or services received, he can protest within the specified period of time (for example, 7 days) and receive his money. Smart contract, using blockchain security tools, reduces forgery and fraud in transactions. Also, if one of the parties does not comply with the obligations of the contract for any reason, the smart contract is used as an acceptable criterion to determine the conditions of the final status of the transaction.

Advantages of smart contract guarantee payment in Ethereum:

Increasing the security of digital transactions, reducing problems such as fraud, forgery, and buyer dissatisfaction with the product that can be used in online markets, in digital currency transactions, and in freelance projects that can be implemented in the Ethereum blockchain.

Conclusion:

Payment guarantee smart contract in Ethereum is a safe and secure solution for conducting digital transactions between two different parties. With this smart contract, transaction security increases and problems such as fraud, forgery, and buyer dissatisfaction with the product are reduced. Also, the use of smart contracts in online markets and digital currency transactions increases the speed and efficiency of transactions. Due to the fact that it can be implemented in the Ethereum blockchain, it can also be used in freelance projects. The smart contract is an efficient and secure solution for conducting digital transactions between two different parties. This smart contract gives assurance to the seller and the buyer that their money is safe and both parties are sure that the transaction will be done transparently and in accordance with the contract. Due to the growing trend of the digital currency market and the increasing use of blockchain technology, the payment guarantee smart contract is an efficient and new tool for conducting digital transactions.

is considered With this smart contract, the security of transactions increases and problems such as fraud, forgery and buyer dissatisfaction with the product are minimized.

Note: Before performing any operation, it is recommended to check the codes carefully and ensure their use in your project. Also, these codes may require additional modifications and adjustments to adapt to specific environments or project requirements.