I agree that Chahda wouldn't send a code you couldn't solve, so my advice is put the code book away.
He took the code book from the shelf and opened it on the table.
The shore-party was, of course, also provided with a code book and set of flags.
Amy and I have a code book with the alphabet in it, said Jessie slowly.
Why, who ever heard of a code book for cabling on baby business?
It had come in code, but Dan was able to translate it without reference to his code book.
For some moments Joe ran through the pages of the code book.
His code book revealed a complicated mass of information which was deciphered at once, with some assistance from him.
Messages sent by the navy code flags cannot be read except by the aid of the code book.
Mr. Bodkin cited our code book with the assistance of which we were able to communicate private messages.