Answer: secretcode

AnswerCrossword Clue
SECRETCODELanguage for private messages
SECRETCODECryptographer's creation
SECRETCODEEnigma output, e.g.
SECRETCODEA spy might crack it
SECRETCODECryptogram
SECRETCODESpy's writing
SECRETCODESomething to crack
SECRETCODEWriting that's hard to read
SECRETCODEA spy might send a message in one
SECRETCODEWho wrote a 2003 best seller about a ...?