title: Get a 28-byte number from uint64 in C
body: <p>I would like to get a 28-byte number from multiple 64-bit inputs.</p>
  
  <p>I want to use the True Random Number Generator of AM3352. It generates an output of 64 bits. And I want to create a 28-byte number that would be randomly generated by the TRNG of the AM3352 and use the "salt" for a password like : Hashed password = password + salt</p>
  
  <p>For example, I get : <code>val1 = 2411177729172638042</code>, <code>val 2 = 11787499938100258610</code>, etc. I need 4 such values to get 28 bytes. I would like to have a 28-byte number from these <code>uint64</code> values.</p>
  
  <p>How to do it?</p>