The development of totally secure computer and telecoms networks has taken a significant leap forward thanks to a successful demonstration between a single sender and multiple receivers – instead of a just single sender and single receiver as has been commonly demonstrated previously.
This could help pave the way for the development of quantum-encrypted comms for applications that demand or seek a security level second-to-none, such as international banking and financial systems, and eventually to all networks.
Researchers at the Australian National University (ANU) in Canberra claim to have been the first in the world to demonstrate communication of information via quantum state sharing. This involved the production and disembodiment of a message in one location and its successful reconstruction to a network of participants in other different locations. The breakthrough builds on earlier quantum transportation work performed by the ANU with laser light in 2002.
In practice, the researchers used crystals, lenses and mirrors to produce a pair of “entangled” laser beams that are then used to communicate securely encrypted information using quantum states. Entanglement refers to a quantum phenomenon that links the properties of two photons of light created at the same time and which can be sent to different places. Because the quantum states of each photon are then related, by forcing one photon into a specific state the other is then also forced to instantaneously to take up a complementary and thus identifiable state. Because the quantum states cannot be measured or copied, because doing so destroys the information they carry, successful eavesdropping is impossible and the light beams carry all reconstruction information with guaranteed security.
A further security side benefit of the ANU network technology is that the encrypted message can only by decoded if successfully received by the majority of its intended recipients. For example, if an encrypted message was sent to a network comprising 15 individuals, a minimum of 8 would be needed to have the necessary information required to reconstruct the original message. It is also claimed that the principles behind this communications system could have major secondary application value to fail-safe mechanisms in the operating systems of proposed future generation, super high speed quantum computers.
The experiment was conducted by ANU PhD student Andrew Lance and Dr Thomas Symul from the ANU, in collaboration with Professor Barry Sanders from the University of Calgary.