Quantum cryptography gets practical

Computerworld - In theory and in labs, quantum cryptography -- cryptography based on the laws of physics rather than traditional, computational difficulty -- has been around for years. Advancements in science and in the world's telecommunications infrastructure, however, have led to the commercialization of this technology and its practical application in industries where high-value assets must be secure.
Protecting information today usually involves the use of a cryptographic protocol where sensitive information is encrypted into a form that would be unreadable by anyone without a "key." For this system to work effectively, the key must be absolutely random and kept secret from everyone except the communicating parties. It must also be refreshed regularly to keep the communications channel safe. The challenge resides in the techniques used for the encryption and distribution of this key to its intended parties to avoid any interception of the key or any eavesdropping by a third party.
Many organizations are advancing quantum technology and bringing it outside academia. Research labs, private companies, international alliances such as the European Union and agencies such as the Defense Advanced Research Projects Agency are investing tens of millions of dollars in quantum research, with projects specifically focused on the challenge of key distribution.
The trouble with key distribution
Huge investment in the late 1990s through 2001 created a vast telecommunications infrastructure resulting in millions of miles of optical fiber laid across the country and throughout buildings to enable high-speed communications. This revolution combined a heavy reliance on fiber-optic infrastructure with the use of open network protocols such as Ethernet and IP to help systems communicate.
Although this investment delivers increased productivity, dependence on optical fiber compounds key distribution challenges because of the relative ease with which optical taps can be used. With thousands of photons representing each bit of data traveling over fiber, nonintrusive, low-cost optical taps placed anywhere along the fiber can siphon off enough data without degrading the signal to cause a security breach. The threat profile is particularly high where clusters of telecommunications gear are found in closets, the basements of parking garages or central offices. Data can be tapped through monitoring jacks on this equipment with inexpensive handheld devices. This enables data to be compromised without eavesdroppers disclosing themselves to the communicating parties.
Another important aspect of this problem is the refresh rate of the keys. Taking large systems off-line to refresh keys can cause considerable headaches, such as halting business operations and creating other security threats. Therefore, many traditional key-distribution systems refresh keys less than once