Early manual and mechanical cryptography - Cryptography: Cracking Codes - page 51

realize far more complex operations than were feasible
manually and, more importantly, they could encrypt and
decrypt faster and with less chance of error.
The firsT sysTems
People have probably tried to conceal information in writ-
ten form from the time that writing developed. Examples
survive in stone inscriptions, cuneiform tablets, and
papyruses showing that the ancient Egyptians, Hebrews,
Babylonians, and Assyrians all devised protocryptographic
systems both to deny information to the uninitiated and
to enhance its significance when it was revealed. The
first recorded use of cryptography for correspondence
was by the Spartans, who as early as 400 bce employed a
cipher device called the scytale for secret communication
between military commanders. The scytale consisted of a
tapered baton, around which was spirally wrapped a strip
of parchment or leather on which the message was then
written. When unwrapped, the letters were scrambled in
order and formed the cipher; however, when the strip was
wrapped around another baton of identical proportions to
the original, the plaintext reappeared. Thus, the Greeks
were the inventors of the first transposition cipher. During
the 4th century bce , Aeneas Tacticus wrote a work entitled
On the Defense of Fortifications, , one chapter of which was
devoted to cryptography, making it the earliest treatise
on the subject. Another Greek, Polybius ( c . 200-118 bce ),
devised a means of encoding letters into pairs of symbols
by a device called the Polybius checkerboard, which is a
true biliteral substitution and presages many elements of
later cryptographic systems. Similar examples of primitive
substitution or transposition ciphers abound in the history