Since there have been intelligent humans, there has been a need for secret codes and messages. History is full of instances where secret codes have been used in wars, to send messages to far-flung regions of a kingdom, or for just plain fun:). A string-based cryptic communication system was used by the ancient Incan administrators, and at last it might be unravelling, thanks to computer analysis of hundreds of different knotted bundles:):).

Incan strings (Courtesy: Stony Brook University)The discovery provides a tantalising glimpse of bureaucracy in the Andean empire and may, for the first time, also reveal an Incan word written in string. Woven from cotton, llama or alpaca wool, the mysterious string bundles - known as Khipu - consist of a single strand from which dangle up to thousands of subsidiary strings, each featuring a bewildering array of knots. Of the 600 or so Khipu that have been found, most date from between 1400 AD and 1500 AD. However, a few are thought to be about 1000 years old.
Anthropologist Gary Urton and mathematician Carrie Brezine at Harvard University think they may have begun unravelling the knotty code. The pair built a searchable database containing key information about Khipu strings, such as the number and position of subsidiary strings and the number and position of knots tied in them. The pair then used this database to search for similarities between 21 Khipus discovered in 1956 at the key Incan administrative base of Puruchuco, near modern day Lima in Peru:):).
The Khipu were used to collate information from different parts of the empire, which stretched for more than 5500 kilometres. Local accountants would forward information on accomplished tasks upward through the hierarchy, with information at each successive level representing the summation of accounts from the levels below.
Completely deciphering the Khipu may never be possible, Urton says, but further analysis of the Khipu database might reveal other details of life. New archaeological discoveries could also throw up some more surprises:):).