Ethereum: How to get addresses from scriptPubKey in segwit transactions?

Ethereum ScriptPubKey Addresses: How to Extract Them from Segwit Transactions

As a developer or data analyst working with Ethereum transactions, you’re likely 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 the “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’ll explore some advanced techniques to extract SPTK addresses from Segwit transactions using Ethereum’s scripting language, Solidity.

Why can’t we just use the scriptPubKey?

In the past, it was possible to extract SPTK addresses directly from raw transaction data by analyzing 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 for extracting SPTK addresses from Segwit transactions. Here’s an example of how you can use it:

const { ethSig } = require('eth-sig');


// Load the transaction data

const txData = ...;


// Extract the scriptSig section

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 would need to be compiled and deployed as a Solidity contract, which can then be used in conjunction with your existing code.

Here’s an example of how you could implement a custom script:

pragma solidity ^0.6.0;


contract SptkExtractor {

    function getSpkAddress(bytes memory txData) public view returns (address) {

        // Load the transaction data

        bytes32 txHash = txData.read(0);

        

        // Parse 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());

        }

        

        // Extract the SPTK address from the signature scheme

        spkAddress = keccak256(rsp);

        

        return spkAddress;

    }

}

Method 3: Using a third-party library and Web3.js

Finally, you can also use a third-party library like web3.js to extract SPTK addresses from Segwit transactions. This method requires more setup and configuration, but provides access to the required libraries and APIs.

Here’s an example of how you could use web3.js with the eth-sig library:

“javascript

// Parse the scriptSig using theeth-sig` library

const sigInfo = ethSig.

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