Apparatus for sending cryptographic key information through a turbulent medium features a radiation generator in a first enclosure for emitting radiation at a predetermined wavelength through first launching means for launching the radiation into turbulent media. A second launching means in a second enclosure is located a distance from the first enclosure for receiving the radiation launched from the first launching means after the radiation has traversed the turbulent media, and focusing the radiation onto detection means for determining a unique cryptographic key.
 The present invention generally relates to secure cryptographic key exchange, and, more specifically to use of natural ambient turbulence to generate and share cryptographic keys. This invention was made with Government support under Contract No. W-7405-ENG-36 awarded by the U.S. Department of Energy. The Government has certain rights in the invention.