title: how to represent message as an integer between 1 and n-1?
body: <p>I am trying to implement simple El-Gamal cryptosystem.</p>
  
  <p>And I can't understand how to represent message as an integer between 1 and n-1.
  The only thing that comes to my mind is:
   if n bit length is k, then divide input message m on t | t &lt; k bits and each piece of bits use as integer number.</p>
  
  <p>I think It is wrong.</p>
  
  <p>So how to represent message as an integer between 1 and n-1? </p>