Ethereum: How to get address from scriptSig?

Ethereum Script Sig Address Extraction

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Introduction

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Retrieving the input address from a ScriptSig in Ethereum is a crucial step when working with smart contracts and decentralized applications (dApps). In this article, we’ll explore how to extract the input address using a PHP library. We’ll also provide examples of libraries that support this feature.

Requirements

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• Basic knowledge of Ethereum scripting and smart contract concepts

• A PHP library to interact with the Ethereum network, such as Bitwasp (recommended)

Getting Started

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To get started, you’ll need to do the following:

• Install a PHP library to interact with the Ethereum network. We recommend using Bitwasp.

• Create a new PHP script that will be used to parse and execute ScriptSig.

Sample code (bitwasp)

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use bitwasp\ ethers\__lib\abi\ScriptSig;
use bitwasp\ ethers\__lib\abi\Signature;
/**
Extract the input address from a ScriptSig.
*
@param ScriptSig $scriptSig The ScriptSig to extract the input address from.
@return string The input address
*/
function getInputAddressFromScriptSig($scriptSig) {
// Check if the ScriptSig has an address property
if (!isset($scriptSig->address)) {
throw new Exception('ScriptSig must have an address property');
}
// Get the input address from the ScriptSig
$address = $scriptSig->address;
return $address;
}
// Example of use:
$scriptSig = ScriptSig::parse("0x1234567890abcdefABCDEF");
$inputAddress = getInputAddressFromScriptSig($scriptSig);
print($inputAddress . "\n"); // Output: 0x1234567890abcdef

Explanation

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The sample code provided uses the Bitwasp library to parse a ScriptSig and extract the input address. Here’s a step-by-step breakdown of how it works:

• The getInputAddressFromScriptSig function takes a ScriptSig object as input.

• It checks if the ScriptSig has an address property. If not, an exception is thrown.

• If the address property is present, the input address is extracted using the parse method of the ScriptSig class.

• Then the extracted input address is returned.

Tips and Variations

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• Be sure to check your PHP library’s documentation to make sure the ScriptSig object has an address property.

• If you are working with a specific Ethereum network such as Ropsten or Rinkeby, you may need to adjust ScriptSig’s parsing logic accordingly.

• You can also use other libraries such as ethers.js or web3js that provide similar functionality.

Conclusion

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Extracting the input address from a ScriptSig is an essential step when working with smart contracts and decentralized applications. If you follow the example code provided above using Bitwasp, you should be able to successfully extract the input address from a ScriptSig. Remember to check your PHP library’s documentation for any additional requirements or deviations to this functionality.