The Collaborative International Dictionary of English v.0.48:

cryptographer \cryp*tog"ra*pher\ (kr?p-t?g"r?-f?r), n.
   1. One who writes in cipher, or secret characters.
      [1913 Webster]

   2. one who studies methods for encoding and decoding
      messages; one who studies cryptography.
      [PJC] Cryptographic

WordNet (r) 3.0 (2006):

cryptographer
    n 1: decoder skilled in the analysis of codes and cryptograms
         [syn: cryptanalyst, cryptographer, cryptologist]