title: How to encrypt something so that can be decrypted using any two of three keys?
body: <p>So say I want to encrypt a file and the only way I want it to be read is if two different people enter their keys. So, for instance there are four keys:</p>
  
  <p>key1, key2, key3, key4.</p>
  
  <p>If I encrypt it with key1 then the following combinations will decypt it:</p>
  
  <ul>
  <li>key2,key3</li>
  <li>key3,key4</li>
  <li>key2,key4</li>
  </ul>
  
  <p>Is this possible using a standard method?</p>