.i.d.) Gaussian random vector that is imperceptibly inserted in a spread-spectrum-like fashion into the perceptually most significant spectral components of the data. We argue that insertion of a watermark under this regime makes the watermark robust to signal processing operations (such as lossy compression

This paper presents a secure spread-spectrum watermarking algorithm for digital images in discrete wavelet transform (DWT) domain. The algorithm is applied for embedding watermarks like patient identification/ source identification or doctors signature in binary image format into host digital

perceptually from the original counterparts, because the purpose of taking the image must not be violated. This paper provides spread spectrum watermarking of the satellite image by choosing a region of interest and embedding the watermark in the same. The reason for choosing a region of interest is an area

that modification of these components can lead to percep-tual degradation of the signal. To avoid this, we propose to insert a watermark into the spectral components of the data using techniques analogous to spread sprectrum communi-cations, hiding a narrow band signal in a wideband channel that is the data

Abstract This article shows the results obtained when using secure spread-spectrum watermarking on gray-scale images in the watermark only attack (WOA) framework. Two secure modulations, natural water-marking (NW) and circular watermarking (CW), are compared with classical insecure modulations

Comparison of secure spread-spectrum modulations

As sensor networks edge closer towards wide-spread deployment, security issues become a central concern. So far, the main research focus has been on making sensor networks feasible and useful, and less emphasis was placed on security. We design a suite of security building blocks that are optimized

Attractive features of time-hopping spread-spectrum multiple-access systems employing impulse signal technology are outlined, and emerging design issues are described. Performance of such communications systems in terms of achievable transmission rate and multiple-access capability are estimated

ABSTRACT Using dealer's quotes and transactions prices on straight industrial bonds, we investigate the determinants of credit spread changes. Variables that should in theory determine credit spread changes have rather limited explanatory power. Further, the residuals from this regression

distortion--robustness tradeoffs than currently popular spread-spectrum and low-bit(s) modulation methods. Furthermore, we show that for some important classes of probabilistic models, DC-QIM is optimal (capacity-achieving) and regular QIM is near-optimal. These include both additive white Gaussian noise