Quantum Cryptography – Tales from the bits

Quantum Cryptography Breached With Lasers

George Bagropoulos — Sat, 18 Sep 2010 08:06:09 +0000

Up until recently quantum cryptography thought to be secure to transmit cryptographic keys. Any attempt to eavesdrop the transmission could be easily detected (based on Heisenberg uncertainty principle). This was proved wrong by the team of researchers from the Norwegian University of Science and Technology (NTNU), the University of Erlangen-Nürnberg and the Max Planck Institute for the Science of Light in Erlangen. The team developed a quantum eavesdropping technique that remotely controls the photon detector. The researchers wrote that someone “can attack the systems with off-the-shelf components, obtaining a perfect copy of the raw key without leaving any trace of her presence.”

Vadim Makarov, one of the researchers, said that “The security loophole we have exposed is intrinsic to a whole class of single-photon detectors, regardless of their manufacturer and model.”

Quantum Cryptography Cracked

George Bagropoulos — Thu, 31 Dec 2009 18:23:00 +0000

Quantum cryptography was thought to be much more secure than all classical cryptography schemes.
This extremely interesting presentation shows a successful attack of an existing quantum key distribution system exploiting a photon detector vulnerability which is probably present in all existing devices. Without Alice and Bob losing their faith in their secure communication, the group recorded 100% of the supposedly secret key.

I have a great interest in quantum cryptography. The above presentation proves another technological assumption wrong.

Breakthrough in quantum cryptography

George Bagropoulos — Tue, 05 May 2009 06:57:00 +0000

(Source: PhysOrg.com) A team from Austria’s Institute for Quantum Optics and Quantum Information (IQOQI) managed to send entangled photons 144 kilometres (90 miles) between the Spanish islands of Las Palmas and the Balearics using satellites
Quantum cryptography is possible over a modern glass fibre net, but because of the high rate of transmission loss, this is limited to around 100 km. To realise future quantum communication networks on a global scale, satellite based systems must be developed and photons transmitted over optical free space distant from the ground.

More information:
http://www.nature.com/nphys/journal/vaop/ncurrent/abs/nphys1255.html