"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

“So the threat to cryptography is well understood due to work by Peter Shor and others. A symmetric algorithm like AES or others standard crypto processes is cut (of) key-size in half, which is a dramatic reduction. ... For key management purposes, against the RSA and the Diffie-Hellman and stuff, they flat-line under a quantum computer.”

Brian Snow, Former Technical Director of the US National Security Agency (NSA), Public Key Cryptography 30th Anniversary Conference, Dec 2006

“Never underestimate the attention, risk, money and time that an opponent will put into reading traffic.”

Robert Morris, former Chief Scientist of the US National Security Agency (NSA), National Computer Security Center, "Crypto '95 invited talks by R. Morris and A. Shamir", 1995