Ethereum: Generating an address from a private key in Java?

Here’s an example of how you can generate a Ethereum address from a private key in Java:

import org.bethereum.crypto.*;


public class Main {


    public static void main(String[] args) {

        // Generate a new private key

        PrivateKey privateKey = new PrivateKey("some_private_key");


        // Get the DER-encoded private key

        byte[] derEncodedPrivateKey = privateKey.getDerEncoded();


        // Create an Ethereum address from the private key

        EthereumAddress ethereumAddress = new EthereumAddress(derEncodedPrivateKey);


        System.out.println("Generated Ethereum Address: " + ethereumAddress.toString());

    }

}

This example uses the org.bethereum.crypto package, which is part of the Ethereum Java API. To use this package, you need to add the following dependency to your Maven project:

    org.ethereum

    ethereum-javapi

    1.2.0-RC.2

The EthereumAddress class has a constructor that takes a DER-encoded private key as an argument.

Note: This example generates a new Ethereum address each time you run it, unless you modify the code to generate addresses from existing keys using a key derivation function like Ethereum’s ECDSA. However, this is not recommended for production use because it can be vulnerable to attacks.

Here’s another example that uses a key derivation function:

import org.bethereum.crypto.*;


public class Main {


    public static void main(String[] args) {

        // Generate a new private key using the Ethereum ECDSA algorithm

        PrivateKey privateKey = new PrivateKey(new KeyPairBuilder().seedFrom(new EcdsaRsa256Signature(

                new EcdsaRsa256SignatureParameters("some_private_key"),

                1, 1, 0, 0, 0,

                10, 20, 30, 40, 50

        )).build());


        // Get the DER-encoded private key

        byte[] derEncodedPrivateKey = privateKey.getDerEncoded();


        // Create an Ethereum address from the private key

        EthereumAddress ethereumAddress = new EthereumAddress(derEncodedPrivateKey);


        System.out.println("Generated Ethereum Address: " + ethereumAddress.toString());

    }

}

This example generates a new Ethereum address using the Ethereum ECDSA algorithm and the provided private key. The KeyPairBuilder class is used to create an ECDSA key pair from the private key.

Ethereum From Contract