title: Read/write to NFC tag with password protection
body: <p>I need to write/read textual data to an NFC tag. The way I am expecting the read/write should work is the following:</p>
  
  <ol>
  <li>First time write I should be able to set password.</li>
  <li>Next time when anyone tries to read OR write, if he has the password then he should be able to do the read/write.</li>
  <li>No other application should be able to modify my tag without the password I set at step 1.</li>
  </ol>
  
  <p>I had one other approach in mind writing encrypted data to the tag once and the write is done make the tag read only. I am able to do this. But now I realize making the tag read-only is not so efficient.</p>
  
  <p>I searched a lot over the internet but did not find any reliable article or guide yet. So if anyone has done password protection of NFC tags please guide me.</p>