Is it possible to create an address using ethereumjs without a Geth node?

Question

I am working on a iOS & Android-App which is interacting with the blockchain via a Geth node behind an API. Is it possible to do the following: 1. generate an address using a package like EthereumJS 2. Sign transactions with it 3. Accept those transactions with the Geth node?

Or is it only possible to generate addresses from a Geth-Node? Thank you!

Answer 1

1. Yes, you can use ethereumjs-wallet to create a wallet client side.

   const wallet = require('ethereumjs-wallet');
   const myWallet = wallet.generate();
   
   console.log(`Address: ${myWallet.getAddressString()}`);
   console.log(`Private Key: ${myWallet.getPrivateKeyString()}`)
   

   Will output something like this:

   Address: 0x31483bb3cae99bf173e5f61f0c62dc398f197b81
   Private Key: 0x96d99fefd214a6cf0e401936bed52c96ddbb82b7e2d51d453ae7b85f115ae20a
   

2. You can use ethereumjs-tx to create and sign transactions.

   const Transaction = require('ethereumjs-tx');
   
   const txData = {
     nonce: '0x00',
     gasPrice: '0x04a817c800',
     gasLimit: '0x5208',
     to: '0x31483bb3cae99bf173e5f61f0c62dc398f197b81',
     value: '0x03e8',
     data: '0x',
     chainId: 3
   };
   
   const tx = new Transaction(txData);
   tx.sign(myWallet.getPrivateKey());
   

3. To send signed transaction to geth you can use web3.eth.sendRawTransaction.

   web3.eth.sendRawTransaction('0x'+tx.serialize().toString('hex'));