Quantum Cryptography Keeping secrets and transmitting information that goes undetected has long been the goal of cryptographers. Codes were written and then deciphered keeping cryptographers constantly searching for the indecipherable code. Until recently that goal seemed unattainable; however, a solution to the once impossible question appears to have emerged. Quantum cryptography delves into the world of very small particles, where there are entirely new ways of building codes. (“Arrives” 2) Quantum cryptography is a relatively recent discovery in the world of cryptography and is still being tested by the government for distance and practicality. More recently, researchers from the government-owned QinetiQ PLC and Ludwig-Maximilans University demonstrated an overnight key exchange using quantum cryptography over a 23.4 km route between the peaks of the Zugspitze and Karwendelspitze mountains in Germany ( Bains 1). To understand how quantum cryptography works, you first need to understand the Heisenberg uncertainty principle. According to Heisenberg, when you try to measure a quantum particle (a very small particle), the particle is altered in such a way that the measurement cannot be completely accurate. The particle is disturbed and its appearance can no longer be determined before the measurement attempt. ("Arrives" 3). In quantum cryptography, there are four different particles. The particles are identified by their position: – (horizontal); | (vertical); / (left diagonal); (right diagonal). Particles are measured by the receiver with a filter, and, predictably, the vertical filter lets vertical particles through, the horizontal filter lets horizontal particles through, and so on. Here, Heisenberg's uncertainty principle through... in the center of the paper... the key that Bob is using, Alice is free to read any message that Bob sends; however, Bob will not be able to decipher everything Alice sends him. While it is virtually impossible to eavesdrop using quantum cryptography, the system is only as reliable as the sender and recipient. Works Cited “Special Report: Quantum Cryptography Arrives.” PC magazine. 6 pages. August 6, 2002. Article A90181639 (Infotrac).Bains, Sunny. "Alice and Bob split up. (Quantum cryptography)." World of laser fire. 2 pages. May 2002. see 38. i.5. Article A86506297 (Infotrac). "The end of the code wars? Quantum cryptography; The uncertainty principle and codes. (Science and Technology)." The Economist (USA). 3 pages. June 23, 2001. Article A75710312 (Infotrac).Peterson, Ivars. “Quantum cheating.” Science news. 2 pages. June 14, 1997. v.151i. 24. Article A19524070 (Infotrac).