"One often hears recommendations for key-sizes of public-key cryptosystems needed to obtain security for 30 years and even 50 years. Anyone wanting a real security of this magnitude should probably take the construction of the quantum computer into consideration."

ECRYPT, “D.PROVI.3 – First Summary Report on Unconditionally Secure Protocols”, January 2005

"My colleagues at MIT and I have been building simple quantum computers and executing quantum algorithms since 1996, as have other scientists around the world. Quantum computers work as promised. If they can be scaled up, to thousands or tens of thousands of qubits from their current size of a dozen or so, watch out!”

Prof Seth Lloyd of MIT, MIT Review 2008

"There is a good chance that large quantum computers can be built within the next 20 years.  This would be a nightmare for IT security if there are no fully developed, implemented, and standardized post-quantum signature schemes."

Prof. Johannes Buchmann, et al, “Post-Quantum Signatures”, Oct 2004, Technische Universität Darmstadt