Verifying Segwit Transactions on Ethereum

The Segregated Witness (Segwit) feature of the Ethereum network allows for the separation of transaction metadata from input data, which increases efficiency and security. However, verifying whether a transaction is indeed Segwit can be a bit complicated. In this article, we will present the simplest method to verify whether a transaction is a Segwit transaction.

Why Segwit Transactions Are Different

Before we delve into the verification methods, let’s briefly explain what makes a transaction Segwit:

• A Segwit transaction has a separate header section (segsig) containing metadata about the sender and recipient addresses.

• The payload (i.e. the data being transferred) is stored in the transaction body.

Simple Method: Check the Transaction Body

A simple way to check if a transaction is a Segwit transaction is to check its data. If it is a Segwit transaction, the segsig field will be present in the transaction body and will contain the specified prefix.

To implement this method:

• Download the Ethereum blockchain data (e.g. from [Etherscan]( or [BlockCypher](

• Load the downloaded JSON file into a programming language such as Python, JavaScript or R.

• Analyze the transaction data and check if it contains the segsig field.

Here is some Python code:

import json
def is_segwit(tx):





Assuming the transaction data is stored as a JSON object
transaction_data = tx['transaction']['data']

Check if there is a segsig field in the transaction body
if 'segsig' is not in transaction_data or transaction_data['segsig'] != b'\x01\x00':
return False 
Not Segwit
return True 
Segwit

Example usage:
transaction = {
'transaction': {
'data': json.dumps({
'from': '0x...',
'to': '0x...',
'value': 10,
'gasprice': '0x...',
'gasLimit': '0x...',
'nonce': '0x...',
'blockNumber': '0x...', 
Optional
'timestamp': '0x...', 
Optional
}),
},
} }
if is_segwit(transaction):
print("Found Segwit transaction!")
otherwise:
print("Not Segwit transaction.")

SeRegWit: a more robust verification method

For a more robust solution, we can use the seRegWit library, which provides a simple API to check if a transaction is a Segwit transaction. You will need to install it using npm or yarn:

npm install seRegWit

Here is a sample code snippet in JavaScript:

const seRegWit = require('seRegWit');
async function verifySegwit(tx) {
try {
const result = wait for seeRegWit. verifyTx ( tx );
if (result. status === 0) {
return true; // Segwit transaction found!
} else {
return false; // Not a Segwit transaction
} }
} catch (error) {
console.error(error); // Error handling
return false;
} }
} }
// Usage example:
const tx = {
// Here goes your Ethereum transaction data...
};
verifySegwit(tx)
.then((result) => console.log(result)) .
.catch((error) => console.error(error));

Conclusion

Checking if a transaction is a Segwit transaction can be done easily using the given methods. The first method is to check the transaction content, while the second method uses the seRegWit library to verify if the transaction has a specific header section (segsig). Choose the approach that best suits your case.

Tips and Variations

• For more robust verification, consider using a combination of both methods: check the payload for Segwit-specific metadata, then verify it using the seRegWit library.