Ethereum ScriptPubKey Addresses: How to Extract Them from Segwit Transactions
As a developer or data analyst who has studied 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 called “proof-of-work” (PoW) using their own unique cryptographic keys.
However, not all SPTKs can be easily extracted from raw transaction data using standard methods. This is because Segwit transactions, which were introduced in 2017, use a separate script (called a “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 custom fields.
To overcome this limitation, we will explore some advanced techniques to extract SPTK addresses from Segwit transactions using Ethereum’s scripting language, Solidity.
Why can’t we use scriptPubKey?
Previously, it was possible to extract SPTK addresses directly from the 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 accessible to standard Ethereum tools and libraries.
Method 1: Using the “eth-sig” library
One way to overcome this limitation is to use a third-party library called “eth-sig”. This library provides an API to extract SPTK addresses from Segwit transactions. Here is an example of its usage:
const { ethSig } = request('eth-sig');
// Load the transaction data
const txData = ...;
// Extract the scriptSig part
const scriptSig = txData.scriptSig;
// Parse the scriptSig using the eth-sig' library
const sigInfo = ethSig.parse(scriptSig);
// Extract the SPTK address from the signature scheme
const spkAddress = sigInfo.spkAddress;
console.log(spkAddress);
Method 2: Using a custom script
Another 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 your existing code.
Here is an example of how you can implement a custom script:
pragma solidity ^0,6,0;
contract SptkExtractor {
function getSpkAddress(bytes memory txData) public view return (address) {
// Load transaction data
bytes32 txHash = txData.read(0);
// Parse transaction hash as 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());
}
// Extract SPTK address from signature scheme
spkAddress = keccak256(rsp);
return spkAddress;
}
}
3. Method 2: Using a Third-Party Library and Web3.js
Finally, you can use a third-party library, such as "web3.js", to extract SPTK addresses from Segwit transactions. This method requires more setup and configuration, but it gives you access to the necessary libraries and APIs.
Here is an example of how you can use the "web3.js" file with the "eth-sig" library:
`javascript
const web3 = request('web3');
const { ethSig } = request('eth-sig');
// Load the Web3 instance
const web3Instance = new web3.Web3(new Web3.providers.HttpProvider('
// Load the transaction data
const txData = ...;
// Extract the scriptSig part
const scriptSig = txData.scriptSig;
// Parse the scriptSig using theeth-sig` library
const sigInfo = ethSig.