title: Implementing access to service with metamask
body: <p>STEP 1: “sign in to website” with metamask</p>
  <p>STEP 2: after user is signed in, ask to make a transaction</p>
  <p>STEP 3: once the user has made transaction, look in the blockchain for the address that sent the tx</p>
  <p>STEP 4: if the transaction shows up in the blockchain, provide access to the service</p>
  <p>STEP 5: save the sender address in a database (mysql) and if in future they access the website again do these checks:</p>
  <ul>
  <li>Is user signed in to the website with metamask?</li>
  <li>Send the users wallet address to backend for a check if they already have made a tx</li>
  <li>If both of these criteria are met, access is provided</li>
  <li>otherwise go to step 2</li>
  </ul>
  <p>My question is, is the following scenario a safe way to implement access?</p>