TheCodeBreakers
An alert censor
noticed that the minute gaps did not occur in natural places, as after
syllables. The hidden messages described Allied anti-submarine tactics
and technical U-boat faults. Some outlined escape plans— which were, of
course, foiled.
The second category of linguistically concealed messages is the
semagram (from the Greek "sema," for "sign"). A semagram is a
steganogram in which the ciphertext substitutes consist of anything but
letters or numbers. The astragal of Aeneas the Tactician, in which yarn
passing through holes representing letters carried the secret message, is
the oldest known semagram. A box of Mah-Jongg tiles might carry a
secret message. So might a drawing in
which two kinds of objects represented the dots and dashes of Morse
Code to spell out a message. The New York censorship station once
shifted the hands and altered the positions of the individual timepieces
in a shipment of watches lest a message be concealed in it.
annaabi.ee 
