http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Prediction-based Reversible Data Hiding Using Empirical Histograms in Images
( Chi-yao Weng ),( Shiuh-jeng Wang ),( Jonathan Liu ),( Dushyant Goyal ) 한국인터넷정보학회 2012 KSII Transactions on Internet and Information Syst Vol.6 No.4
This paper presents a multilevel reversible data hiding method based on histogram shifting which can recover the original image losslessly after the hidden data has been extracted from the stego-image. The method of prediction is adopted in our proposed scheme and prediction errors are produced to explore the similarity of neighboring pixels. In this article, we propose two different predictors to generate the prediction errors, where the prediction is carried out using the center prediction method and the JPEG-LS median edge predictor (MED) to exploit the correlation among the neighboring pixels. Instead of the original image, these prediction errors are used to hide the secret information. Moreover, we also present an improved method to search for peak and zero pairs and also talk about the analogy of the same to improve the histogram shifting method for huge embedding capacity and high peak signal-to-noise ratio (PSNR). In the one-level hiding, our method keeps image qualities larger than 53 dB and the ratio of embedding capacity has 0.43 bpp (bit per pixel). Besides, the concept with multiple layer embedding procedure is applied for obtaining high capacity, and the performance is demonstrated in the experimental results. From our experimental results and analytical reasoning, it shows that the proposed scheme has higher PSNR and high data embedding capacity than that of other reversible data hiding methods presented in the literature.
A Cryptographic Key Assignment Scheme with Adaptable Time-token Constraint in a Hierarchy
Hsing-Chung Chen,Shiuh-Jeng Wang,Jyh-Horng Wen 보안공학연구지원센터 2008 International Journal of Multimedia and Ubiquitous Vol.3 No.4
A scheme, which uses flexible cryptographic key management upon adaptable time-token constraint for a user hierarchy access control (UHAC) scheme, is proposed in this paper. For adapting the changeability in a UHAC system, we propose a technique of assigning independent time-token which is distributed by a trusted agency server to reply an authorized user for once secure access request. The key feature of the technique is to adapt some secure parameters in distributed time-token for responding to each legal access request. Further, all class keys will be updated proactively by the concept of proactive key management, which makes the advantage that is proven and free from the scenario of the collusive attack example which proposed by Yi et al. in [18]. This cryptographic key assignment scheme based on the difficulty in solving a discrete logarithm, with adaptable time-token constraint, can achieve better security and more efficient management, than the conventional UHAC scheme. Besides, our scheme provides a flexible manner and dynamic key management to increase the availability of user access in UHAC structure.
Chung-Wei Chen,Shiuh-Jeng Wang,Yuh-Ren Tsai 보안공학연구지원센터 2008 International Journal of Hybrid Information Techno Vol.1 No.4
In this paper, we propose a new pairwise key agreement, TLPKA (Tangent Line Pairwise Key Agreement), for establishing a secure link between members in an ad hoc network. With pairwise keys, data transmitted in ad hoc networks can be protected from the eavesdropping of outsiders. These pairwise keys can also be used to authenticate members in ad hoc networks. In addition, due to the property of uniqueness of pairwise keys, it also provides non-repudiation for data transmitting. In our scheme, we propose a new idea for the design of pairwise key agreements in an ad hoc network. Our scheme is based on the geometrical property of the tangent line and the mechanisms in our scheme are inspired by the Shamir secret sharing scheme. Our schemes also provide reciprocal authentication among node communicants. The robustness of our scheme is based on the DH problem and the indefinite solutions in coordinate geometry. In addition, we compare our scheme with other schemes. Although there is a higher overhead associated with our scheme, it maintains a higher security level than the other schemes.