We study the secrecy properties of Gaussian states under Gaussian operations. Although such operations are useless for quantum distillation, we prove that it is possible to distill a secret key secure against any attack from sufficiently entangled Gaussian states with nonpositive partial transposition. Moreover, all such states allow for key distillation, when Eve is assumed to perform finite-s...

The problem of dephasing channel discrimination is addressed for finite-dimensional systems. In particular, the optimization with respect to input states without energy constraint solved analytically qubit, qutrit and ququart. Additionally, it shown that resorting side entanglement assisted strategy completely useless in this case.

A mailed questionnaire was sent to 2712 subjects asking about respiratory symptoms, and a raffle for three prizes of 50 pounds, 30 pounds, and 20 pounds was organised. The response rate in the 1762 who were told about the raffle was no higher than for 950 subjects who served as controls.

The A5/1 algorithm is one of the most famous stream cipher algorithms used for over-the-air communication privacy in GSM. The purpose of this paper is to analyze several weaknesses of A5/1, including an improvement to an attack and investigation of the A5/1 state transition. Biham and Dunkelman proposed an attack on A5/1 with a time and data complexity of 239.91and 221.1, ...

Information overload is one of the biggest problems currently omnipresent in the word largest network, the Internet. No general solution exists therefore it is important to handle this problem at least in certain areas. Large collections of articles are available to the users of the Internet. Since technology is very easy to handle for information providers, literally every person who has acces...