Ethereum: A Guide to Programmatically Verifying Bitcoin Receipts
If you are building a website that allows users to send bitcoins to a new, disposable address, you need to implement a way to verify when a payment has been received. In this article, we will explore how this can be achieved using Ethereum smart contracts and the Web3.js library.
What is a Bitcoin receipt?
A Bitcoin receipt (or transaction) is a message that a miner or individual user sends to the blockchain network, confirming that they have successfully confirmed their transaction. When a user sends bitcoins to a new address, the recipient receives this receipt as part of the transaction confirmation process.
Programmatically Controlled Checksum Verification
To programmatically verify when a payment has been received, you need to use Ethereum smart contracts and the Web3.js library. Here is a high-level overview of the steps:
- Create New Contract
: Create a new Solidity contract on the Ethereum blockchain that will process Bitcoin transactions. This contract contains the logic for verifying receipts.
- Define Receive Event: Define an event that fires when a payment is received, e.g. B. “Payment Received”.
- Implement Verification Logic: In the verifyReceipt function, verify that the transaction sent to the new address matches the expected signature of the receipt message.
- Update Blockchain Status: If the receipt is valid, update the blockchain status with the new balance and any additional information.
Code Example
Here is an example of how this could be implemented using Solidity, Web3.js, and the Ethereum ERC-20 token standard.
pragma hardness ^0,8,0;
import "
import "
Contract Receipt Verifier {
// Define the confirmation event
Event PaymentReceived(uint256 recipient, uint256 amount);
// Define the receipt verification function
function verifyReceipt(
payee address,
uint256 amount,
string memory signature
) public return (bool) {
// Verify that the transaction matches the expected signature
require(bytes(signature).length == 42, "Invalid signature");
// Get the transaction data
TransactionData storage txData = getTransactionData(recipient, amount);
// Check if the transaction is valid and has a valid signature
request(txData.transactionHash != address(0), "Invalid transaction");
request(txData.signature != "", "Signature is empty");
return true;
}
// Define a function to retrieve transaction data
function getTransactionData(
payee address,
uint256 amount
) return internalView(TransactionData storage) {
Transaction tx = txs[recipient][amount];
return TxData storage txData;
}
}
// Define the structure of the received message
struct ReceiptMessage {
byte32 signature;
string message;
}
// Define the structure of the transaction data
struct TransactionData {
address recipient;
uint256 amount;
}
// Define the transaction structure
struct TxData {
payee address;
uint256 amount;
string signature;
}
Explanation
In this example, we have defined a “ReceiptVerifier” contract with two functions: “verifyReceipt” and “getTransactionData”. The “verifyReceipt” function verifies that the transaction matches the expected signature of the received message. It uses the Web3.js library to retrieve the transaction data from the blockchain.