Verisign Labs
Tech Talks

Tech Talks are presentations from invited guests about issues related to Internet technology.

Quantum computers and public-key cryptosystems

Event Description

Molecular nanotechnology, the ability to economically manufacture most arrangements of atoms permitted by physical law, is going to fundamentally alter our manufacturing technology. It will let us make remarkably light and strong materials, nanorobotic medical devices able to heal and cure even the gravest of injuries, and perhaps most obviously molecular computers orders of magnitude more powerful than any that exist today. Molecular nanotechnology will let us build and interconnect mole quantities of atomically precise logic gates in the complex patterns required by modern computer architectures. Beyond this, molecular nanotechnology should let us build quantum computers (QCs), if this has not been achieved earlier by other methods. This implies that, one way or another, QCs are in our future. This, of course, means all of our existing public-key cryptosystems (PKCSs) will become vulnerable to attack. As the time to develop new, QC-resistant PKCSs is long, the time to certify them is long, the time to standardize them is long, the time to deploy them is long, and the time for existing systems to finally be replaced is long, even if a QC is 20 years away starting the process today might already be too late. And no one really knows how long it might be before someone has a QC.

We should begin immediate development and deployment of a suite of conventional cryptographic protocols that do not use PKCSs to replace today's widely used public-key based protocols. AES and SHA-2 or SHA-3 can be used now. Conventional key distribution protocols using key distribution centers are well known. Digital signatures believed to be QC-resistant are known. This effort should be relatively straightforward and could proceed much more rapidly.

About Dr. Ralph Merkle

Dr. Ralph Merkle presentation on Quantum Computers

Dr. Merkle received his Ph.D. from Stanford University in 1979 where he co-invented public key cryptography. He joined Xerox PARC in 1988, where he pursued research in security and computational nanotechnology until 1999. He was a Nanotechnology Theorist at Zyvex until 2003, when he joined the Georgia Institute of Technology as a Professor of Computing until 2006. He is now a Senior Research Fellow at the Institute for Molecular Manufacturing, on the faculty at Singularity University, a Director of Alcor, and a co-founder of the Nanofactory Collaboration. He chaired the Fourth and Fifth Foresight Conferences on Nanotechnology. He was co-recipient of: the Feynman Prize for Nanotechnology for theory, the ACM's Kanellakis Award for Theory and Practice, the IEEE Kobayashi Award, the RSA Award in Mathematics, the IEEE Hamming Award; a Fellow of the IACR, a Fellow of the Computer History Museum, and a National Inventor’s Hall of Fame Inductee. Dr. Merkle has fourteen patents, has published extensively and has given hundreds of talks. His home page is at

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