ganache-cli how to read private key from account json file

Question

I am running ganache-cli through a node application:

const ganache = require('ganache-core');
const ethers = require('ethers');

const provider = new ethers.providers.Web3Provider(
  ganache.provider({
    total_accounts: 5,
    account_keys_path: './accounts.json',
    gasPrice: 20000000000,
    gasLimit: 20000000000,
    default_balance_ether: 100
  })
);

This runs the ganache-cli and output acocunt details in accounts.json. The file looks like this:

{
   "addresses":{
      "0x73f5b3f74db1b37927696c280c04d544f4e9ff64":{
         "secretKey":{
            "type":"Buffer",
            "data":[88, 17, .....]
         },
         "publicKey":{
            "type":"Buffer",
            "data":[13, 52, .....]
         },
         "address":"0x73f5b3f74db1b37927696c280c04d544f4e9ff64",
         "account":{
            "nonce":"0x",
            "balance":"0x056bc75e2d63100000",
            "stateRoot":"0x56e81f171bcc55a6ff8345e692c0f86e5b48e01b996cadc001622fb5e363b421",
            "codeHash":"0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470"
         }
      }
   }
}

I can see the account address, but how can I decode/get the private key from this information?

Answer 1

You cannot get the private key from accounts directly, but there's a few workarounds to do this with ganache-cli.

1. Specify a mnemonic phrase with the -m option, e.g. ganache-cli -m "stereo consider quality wild fat farm symptom bundle laundry side one lemon", this will derive private keys from the mnemonic phrase (with the derivation path m/44'/60'/0'/0/n.

2. Use the --account_keys_path option to save all private keys to a file, e.g. ganache-cli --account_keys_path keys.json. This will result in a JSON file with all addresses, private keys and public keys.

3. Use the --account option to manually specify a private key and balance, e.g. ganache-cli --account "0x31c354f57fc542eba2c56699286723e94f7bd02a4891a0a7f68566c2a2df6795,1000000000000000000". This will assign 1 ETH (= 1000000000000000000 Wei) to the address corresponding to this private key. You can use the --account option multiple times, with different private keys.