cryptogrammatist
/ˌkrɪptəˈɡramətɪst/(also cryptogramatist)
noun
A person who studies or deciphers cryptograms.
Origin
Late 19th century; earliest use found in Southern Magazine. From crypto- + ancient Greek γραμματ-, γράμμα letter + -ist, after cryptogram and anagrammatist, pangrammatist, epigrammatist.