title: Is there any unique encoding and decoding functions in php?
body: <p>Here we have a scenario to encode file name and want to decode it while retrieving.
  if i encode it with md5 i cant decode it because it is one way hashing and if i encode it with 'base64_encode' then if two files with same name will cause conflict to my data while retrieving.</p>
  
  <p>So i want to know if there in any unique encoding function in PHP to encode and later to decode.</p>
  
  <p>Thanks in advance!!!!</p>