Secret key generation from Gaussian sources using lattice hashing

We propose a simple yet complete lattice-based scheme for secret key generation from Gaussian sources in the presence of an eavesdropper, and show that it achieves strong secret key rates up to 1/2 nat from the optimal in the case of "degraded" source models. The novel ingredient of our scheme is a lattice-hashing technique, based on the notions of flatness factor and channel intrinsic randomness. The proposed scheme does not require dithering.Comment: 5 pages, Conference (ISIT 2013

Secret key generation from Gaussian sources using lattice-based extractors

We propose a lattice-based scheme for secret key generation from Gaussian sources in the presence of an eavesdropper, and show that it achieves the strong secret key capacity in the case of degraded source models, as well as the optimal secret key / public communication rate trade-off. The key ingredients of our scheme are a lattice extractor to extract the channel intrinsic randomness, based on the notion of flatness factor, together with a randomized lattice quantization technique to quantize the continuous source. Compared to previous works, we introduce two new notions of flatness factor based on $L^1$ distance and KL divergence, respectively, which are of independent interest. We prove the existence of secrecy-good lattices under $L^1$ distance and KL divergence, whose $L^1$ and KL flatness factors vanish for volume-to-noise ratios up to $2\pi e$. This improves upon the volume-to-noise ratio threshold $2\pi$ of the $L^{\infty}$ flatness factor

Secure Strong Coordination

We consider a network of two nodes separated by a noisy channel, in which the source and its reconstruction have to be strongly coordinated, while simultaneously satisfying the strong secrecy condition with respect to an outside observer of the noisy channel. In the case of non-causal encoding and decoding, we propose a joint source-channel coding scheme for the secure strong coordination region. Furthermore, we provide a complete characterization of the secure strong coordination region when the decoder has to reliably reconstruct the source sequence and the legitimate channel is more capable than the channel of the eavesdropper

Towards a Quantum Steganographic Capacity of Lossy Bosonic Channels

Quantum steganography is the extension of steganography to the quantum setting, wherein a quantum protocol (e.g.: a quantum error-correcting code) is used to hide classical or quantum information. Because of the unique nature of quantum states and channels, quantum steganography can be stronger than classical steganography. A lot of effort has been devoted to characterizing how much information can be embedded into various quantum channels with or without noise, and recently, several quantum steganography protocols have been developed and analyzed that improve on earlier work by exploiting a concept known in information theory as channel resolvability. This paper first provides a concise background survey of specific topics from relevant disciplines in classical as well as quantum information theory, and then presents a formulation of the problem concerning the characterization of the steganographic capacity for a specific type of quantum channel called the lossy bosonic channel.Undergraduat