Cryptology ePrint Archive: Report 2007/004

Cryptanalysis of Hwang-Chang’s a Time-Stamp Protocol for Digital Watermarking

*Jue-Sam Chou, Yalin Chen, Chung-Ju Chan

Abstract: In 2005, Hwang et al. [17] proposed a time-stamping protocol for digit watermarking. They claimed that their scheme is secure against attacks. However, in this article, we will show that their scheme is not secure enough for that when the owner of the image sends both the encrypted session key and image to the TSS, the attacker can intercept these transmitted data. Then, he can launch an off-line attack to analyze these intercepted data. We will describe the attacker’s action in this article. After that, we propose an improved scheme to prevent this off-line attack.

Category / Keywords: cryptographic protocols / Digital watermarks; Copyright protection; Time-stamping

Date: received 3 Jan 2007

Contact author: jschou at mail nhu edu tw

Available format(s): PDF | BibTeX Citation

Version: 20070104:075826 (All versions of this report)

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