title: How to convert seeds into private key?
body: <p>how to <strong>convert bip39 mnemonic seed phrase into private key</strong> without any libraries like <em>web3</em> or <em>ethers.js</em><br />
  basically I'm trying to replicate my metamasks wallets private key</p>
  <p>so I would like to write a function that takes my seed words as my input and return the private key for ethereum based wallets</p>
  <pre class="lang-dart prettyprint-override"><code>privateKey = function([seed_1, seed_2, ..., seed_12]);
  </code></pre>
  <p>Where do I get started?</p>