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Proceedings Paper

Encryption techniques to the design of e-beam-generated digital pixel hologram for anti-counterfeiting
Author(s): Hau Ping Chan; Nai-Keng Bao; Wing On Kwok; Wing Han Wong
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Paper Abstract

The application of Digital Pixel Hologram (DPH) as anti-counterfeiting technology for products such as commercial goods, credit cards, identity cards, paper money banknote etc. is growing important nowadays. It offers many advantages over other anti-counterfeiting tools and this includes high diffraction effect, high resolving power, resistance to photo copying using two-dimensional Xeroxes, potential for mass production of patterns at a very low cost. Recently, we have successfully in fabricating high definition DPH with resolution higher than 2500dpi for the purpose of anti-counterfeiting by applying modern optical diffraction theory to computer pattern generation technique with the assist of electron beam lithography (EBL). In this paper, we introduce five levels of encryption techniques, which can be embedded in the design of such DPHs to further improve its anti-counterfeiting performance with negligible added on cost. The techniques involved, in the ascending order of decryption complexity, are namely Gray-level Encryption, Pattern Encryption, Character Encryption, Image Modification Encryption and Codebook Encryption. A Hong Kong Special Administration Regions (HKSAR) DPH emblem was fabricated at a resolution of 2540dpi using the facilities housed in our Optoelectronics Research Center. This emblem will be used as an illustration to discuss in details about each encryption idea during the conference.

Paper Details

Date Published: 19 April 2002
PDF: 8 pages
Proc. SPIE 4677, Optical Security and Counterfeit Deterrence Techniques IV, (19 April 2002); doi: 10.1117/12.462718
Show Author Affiliations
Hau Ping Chan, City Univ. of Hong Kong (Hong Kong)
Nai-Keng Bao, City Univ. of Hong Kong (Hong Kong)
Wing On Kwok, City Univ. of Hong Kong (Hong Kong)
Wing Han Wong, City Univ. of Hong Kong (Hong Kong)

Published in SPIE Proceedings Vol. 4677:
Optical Security and Counterfeit Deterrence Techniques IV
Rudolf L. van Renesse, Editor(s)

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