Read more at: http://phys.org/news/2014-02-quantum-scheme-memories.html#jCp
Quantum mechanics offers the potential for creating communication technologies with an inherently higher security level than today's classical technologies. Using quantum digital signatures (QDS), for example, messages can be sent to multiple recipients with the guarantee that the messages cannot be forged or tampered with.
"QDS provides essentially all features for which standard 'classical' digital signatures are used in modern communication—guaranteed authenticity, integrity and transferability of messages," Erika Andersson at Heriot-Watt University in Edinburgh, UK, told Phys.org. "The need for these features is ubiquitous in the modern e-world. They are used regularly in, for example, online banking, email systems, and smart electrical grids."
However, all QDS schemes proposed so far require advanced quantum memories capable of storing millions of qubits for months or even years. In contrast, today's state-of-the-art quantum memories cannot store information for longer than a few minutes, which makes all QDS schemes proposed so far unfeasible.
Now in a new paper published in Physical Review Letters, Andersson and UK-based coauthors Vedran Dunjko and Petros Wallden from Croatia and Greece, respectively, have proposed a QDS scheme that does not require any quantum memory, making the scheme feasible with current technology.