Here is an article about a perfect encryption

http://www.discover.com/may_02/gther...=feattech.html

Theoretically, perfect encryption has been around for a long time. In 1918 American mathematician Gilbert Vernam invented the one-time cipher, which substitutes a random number or letter for each character in a message. As long as you don't reuse that random sequence for subsequent messages, nobody can break the code. But to employ the code, you must send the sequence—the key that unscrambles the encrypted message—to the intended receiver.
Of course a true perfect encryption system is hard to make because some were along the line the data has to appear in an unencrypted state so people can comprehend it.