We consider the notion of canonical attacks, which are the cryptographic analog of the canonical forms of a one-mode Gaussian channel. Using this notion, we explore the connections between the degradability properties of the channel and its security for quantum key distribution. Finally, we also show some relations between canonical attacks and optimal Gaussian cloners.

Reply to Comments on " Quantum Key Distribution for d-level systems for generalized Bell states " [Phys. Rev. A, 052331, (2002)] and " Quantum secret sharing based on a reusable Greenberger-Horne-Zeilinger states as secure carriers " [Phys. Abstract We show that the criticisms of two recent comments [1, 2] on the insecurity of quantum key distributions proposed in [3] and [4] and the secret sha...

Der sicheren Übertragung und Aufbewahrung vertraulicher Daten kommt in unserer von Information dominierten Gesellschaft immer grössere Bedeutung zu. Die heute gebräuchlichen Verfahren zur Datenverschlüsselung bieten allerdings nur berschränkte, so-genannt berechenmässige, Sicherheit. Das bedeutet, dass diese prinzipiell von einem Angreifer, der über genügend Rechenleistung (zum Beispiel einen, ...

We report on a feasibility study of a free-space Quantum Key Distribution setup operating at a mid-infrared wavelength. Alice sends polarization-coded pseudo-single photons from a Quantum Cascade Laser at 4.6 μm to Bob, who uses a nonlinear crystal and a Silicon Avalanche Photodiode to perform the detection via Sum Frequency Generation. Theoretical predictions, based on a proof-of-principle exp...

Wireless sensor networks is composed of a large number of randomly deployed sensor nodes with limited computing ability and memory space. These characteristics gives rise to much challenge to key agreement. General key agreement schemes like KDC, PKI and Diffie-Hellman key exchange schemes are not applicable to the sensor networks. Several key distribution schemes have been proposed specificall...

At Eurocrypt'95, Desmedt suggested a scheme which allows individuals to en-crypt in such a way that the receiver can be traced by an authority having additional information. This paper shows that the proposed scheme does not have the required properties, by devising three non-speciied protocols misleading the authority. We also discuss how to repair Desmedt's scheme, such that our attacks are n...

In this paper we propose a new protocol to manage multicast key distribution. The protocol is based on the use of orthogonal systems in vector spaces. The main advantage in comparison to other existing multicast key management protocols is that the length and the number of the messages which have to be sent are considerably smaller. This makes the protocol especially attractive when the number ...

Wireless sensor networks consist of sensor nodes with limited computational and communication capabilities. This paper deals with mobile sensors which are divided into clusters based on their physical locations. Efficient ways of key distribution among the sensors and inter and intra cluster communications are examined. The security of the entire network is considered through efficient key mana...

We revisit a key agreement scheme presented by Leighton and Micali [11], generalize the scheme, and present a new framework of tree-based key distribution pattern (TKDP). We presents a method of constructing TKDPs from cover-free families. We show the existence of TKDPs by probabilistic method. We can reduce the upper bounds on the minimum number of rows of (t, w, T )-TKDPs, which are obtained ...