Information hiding for digital holograms by electronic partial encryption methods

This paper was devoted to information hiding for a digital hologram which is the most valuable image content. In our approach we selectively encrypt a subset of the data using a conventional encryption technique to find a useful trade-off between encryption effect and its cost. We included three data domains: hologram-domain, DCT-domain, and DWT-domain. In each domain also, various possible choices were examined. The encryption schemes are composed on the basis of the energy distribution. The cost was estimated with the processing time consisting of transform time and encryption time, while the effect was examined basically with eye examination with NC value and PSNR value as the auxiliary values. We examined the properties of a digital hologram and energy distribution in each domain first. Then, the constructed schemes were compared in terms of cost-and-effect and the best choices were provided for some application situations. (c) 2007 Elsevier B.V. All rights reserved.