Noise Keeps Spooks Out of the Loop New Scientist (05/23/07) Palmer, Jason D.
as it appeared in the May 30, 2007 edition of ACM TechNews.
Texas A&M computer engineering professor Laszlo Kish has developed a secure communication system that he says is more secure, more accurate, and can be used over greater distances than quantum cryptography keys. Kish's cipher device uses a property called thermal noise, which is generated by the natural agitation of electrons within a conductor whenever any amount of voltage is passed through it, but varies depending on the resistance of the conductors. The system can be used to send information, or an encryption key, along any wire, including telephone lines and network cable between two users. Each user has a pair of conductors, one produces high resistance, the other low. When both users select the same type of resistor, either a high amount of noise or a low amount of noise will be produced, signaling both to ignore any communication. When the both chose a different type, an intermediate level of thermal noise is produced, allowing messages to be sent. Kish's cipher successfully sent a secure message down a wire 2,000 kilometers long, much farther than the best quantum key distribution (QKD) devices that have been tried so far. Tests show that a signal sent using Kish's device was received with 99.98 percent accuracy, and only 0.19 percent of bits are vulnerable to eavesdropping. Kish's system is also more durable and less expensive, as dust, heat, and vibration can damage QKD devices. Click Here to View Full Article
