Ethereum ScriptPubKey Address: How to Extract Them from Segwit Transactions
As a developer or data analyst working with Ethereum transactions, you are probably familiar with the concept of scriptpubkey (SPTK) addresses. These addresses are used in Ethereum transactions and are generated by solving complex mathematical puzzles known as “proof of work” (PoW) using your own unique cryptographic keys.
However, not all SPTKs can be easily extracted from raw transaction data using standard methods. This is because Segwit transactions introduced in 2017 use a separate script (known as “scriptSig”) to store additional metadata and parameters for each transaction. The scriptSig section contains information such as the sender’s public address, signature scheme, and other configurable fields.
To overcome this limitation, we will look at some advanced methods of extracting SPTK addresses from Segwit transactions using the Ethereum scripting language, Solidity.
Why can’t we just use scriptPubKey?
Previously, it was possible to extract SPTK addresses directly from raw transaction data by parsing the scriptSig section. However, with the introduction of Segwit transactions, the additional metadata stored in this section is no longer available to standard Ethereum tools and libraries.
Method 1: Using the eth-sig' library
One way to get around this limitation is to use the third-partyeth-sig’ library. This library provides an API for extracting SPTK addresses from Segwit transactions. Here is an example of how it can be used:
const { ethSig } = require('eth-sig');
// Load transaction data
const txData = ...;
// Extract scriptSig section
const scriptSig = txData.scriptSig;
// Analysis of scriptSig using the eth-sig' library
const sigInfo = ethSig.parse(scriptSig);
// Extracting the SPTK address from the signature scheme
const spkAddress = sigInfo.spkAddress;
console.log(spkAddress);
Method 2: Using a Custom Script
The second approach is to implement a custom script that extracts the SPTK address from the Segwit transaction. This script needs to be compiled and deployed as a Solidity contract, which can then be used with existing code.
Here is an example of how to implement a custom script:
solidity
pragma solidity ^0.6.0;
contract SptkExtractor {
function getSpkAddress(bytes memory txData) public view returns (address) {
// Load transaction data
bytes32 txHash = txData.read(0);
// Analyze the transaction hash as an Ethereum signature
address spkAddress;
bytes4[] memory rsp = new bytes4[64];
uint8[] memory sigs = txHash.read(1);
for (uint256 i = 2; i < 65; i++) {
rsp[i] = bytes4(sigs[i].byte());
}
// Extracting the SPTK address from the signature scheme
spkAddress = keccak256(rsp);
return spkAddress;
}
}
web3.js
Method 3: using a third-party library and Web3.jsFinally, you can also use a third-party library such as
to extract SPTK addresses from Segwit transactions. This method requires more setup and configuration, but provides access to the necessary libraries and APIs.web3.jsHere is an example of how to use
with theeth-siglibrary:
javascript
const web3 = require('web3');
const { ethSig } = require('eth-sig');
// Load the Web3 instance
const web3Instance = new web3.Web3(new Web3.providers.HttpProvider('
// Load transaction data
const txData = ...;
// Extract scriptSig section
const scriptSig = txData.scriptSig;
// Analysis of scriptSig using the eth-sig' library
const sigInfo = ethSig.