arXiv subjects

Kevin Birnbaum

Publications and source records attributed to Kevin Birnbaum.

2 recordsLinked to original sources

arXiv2008

Reply to Comment on "Exposed-key weakness of $αη$"

We address criticism of the Letter "Exposed-Key Weakness of $αη$" in the Comment by Nair and Yuen. The Comment claims that the Letter does not show insecurity of $αη$ because our approximation for the eavesdropper's entropy on the encrypted key is invalid. We present simulations which show that, on the contrary, our estimate is in close agreement with numerical calculations of the actual entropy over the applicable domain. We additionally discuss some ways in which our views on security requirements differ from the views given in the Comment.

quant-ph↗

arXiv2008

Exposed-key weakness of $αη$

The $αη$ protocol given by Barbosa \emph{et al.}, PRL 90, 227901 (2003) claims to be a secure way of encrypting messages using mesoscopic coherent states. We show that transmission under $αη$ exposes information about the secret key to an eavesdropper, and we estimate the rate at which an eavesdropper can learn about the key. We also consider the consequences of using further randomization to protect the key and how our analysis applies to this case. We conclude that $αη$ is not informationally secure.

quant-ph↗