title: Why is the key space for a substitution cipher Factorial N
body: <p>I'm taking a crypto course, and we're going over substitution ciphers and their Key space. 
  per the instructor, the key space is 26! (approx 2^88) for the English alphabet. there is no reference to key length, probably because a subst cipher's length would be a function of the length of the alphabet, just as the number of options would. </p>
  
  <p>per <a href="http://en.wikipedia.org/wiki/Key_space_%28cryptography%29" rel="nofollow">wikipedia</a> the keyspace is the set of all possible keys of a certian length, and is calculated in the same way brute force try counts would be options^length or in this case 26^26. </p>
  
  <p>so what am I not getting here?  </p>