Simple and secure quantum key distribution with biphotons

I. Bregman*, D. Aharonov, M. Ben-Or, H. S. Eisenberg

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

25 Scopus citations


The best qubit one-way quantum-key-distribution (QKD) protocol can tolerate up to 14.6% in the error rate. It has been shown how this rate can be increased by using larger quantum systems. The polarization state of a biphoton can encode a three-level quantum system-a qutrit. The realization of a QKD system with biphotons encounters several problems in generating, manipulating, and detecting such photon states. We define those limitations and find within them a few protocols that perform almost as well as the ideal qutrit protocol. One advantage is that these protocols can be implemented with minor modifications into existing single photon systems. The security of one protocol is proved for the most general coherent attacks and the largest acceptable error rate for this protocol is found to be around 17.7%. For comparison, the security of the best possible qutrit protocol of four mutually unbiased bases was also rigorously analyzed against general attacks, with a proven bound on the acceptable error rate of 21.1%.

Original languageAmerican English
Article number050301
JournalPhysical Review A - Atomic, Molecular, and Optical Physics
Issue number5
StatePublished - 8 May 2008


Dive into the research topics of 'Simple and secure quantum key distribution with biphotons'. Together they form a unique fingerprint.

Cite this