TheCodeBreakers
Cryptology arose
independently in many places, and in most of them it died the deaths of
its civilizations. In other places, it survived, embedded in a literature,
and from this the next generation could climb to higher levels. But
progress was slow and jerky. More was lost than retained. Much of the
history of cryptology of this time is a patchwork, a crazy quilt of
unrelated items, sprouting, flourishing, withering. Only toward the
Western Renaissance does the accreting knowledge begin to build up a
momentum. The story of cryptology during these years is, in other words,
exactly the story of mankind.
China, the only high civilization of antiquity to use ideographic
writing, seems never to have developed much real cryptography—
perhaps for that reason. In one case known for military purposes, the
11th-century compilation, Wu-ching tsung-yao ("Essentials from Military
Classics"), recommended a true if small code. To a list of 40 plaintext
annaabi.ee 
