Associate Professor Margaret Reid of Swinburne University said that Einstein’s reservations about quantum mechanics were highlighted in a phenomenon known as “spooky action at a distance” – which is the strange way entangled particles stay connected even when separated by large distances.
“Until now the real application of this has been for messages being shared between two people securely without interception, regardless of the spatial separation between them,” Reid said. “In this paper we give theoretical proof that such messages can be shared between more than two people, and may provide unprecedented security for a future quantum internet.”
In the 1990s, scientists realised you can securely transmit a message by encrypting and using a shared key generated by Einstein’s strange entanglement to decode the message from the sender and receiver. Using the quantum key meant that the message was completely secure from interception during transmission.
Sending Einstein’s entanglement to a larger number of people means that the key can be distributed among all the receiving parties, so they must collaborate to decipher the message. Reid says that this makes the message even more secure.
“We found that a secure message can be shared by up to three to four people, opening the possibility to the theory being applicable to secure messages being sent from...
