• 디지털산업정보학회논문지
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• 제9권3호
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• pp.79-89
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• 2013

This paper proposes a watermarking scheme to protect ownership of a digital hologram, an ultra-high value-added content. It performs pre-defined levels of quad-tree Fresnelet transforms. The relationship among the same-positional-blocks is extracted as the digital pre-watermark. For the relationship, we use properties of a digital hologram that a hologram pixel retains all the information of the object and that the same size of partial holograms reconstructs the same size of object but different in their view points. Also we mix a set of private data with the pre-watermark and the result is encrypted by a block cipher algorithm with a private key. Experimental results showed that the proposed scheme is very robust for the various malicious and non-malicious attacks. Also because it extracts the watermarking data instead of inserting, the watermarking process does not harm the original hologram data. So, it is expected to be used effectively for invisible and robust watermark for digital holograms.

• 한국통신학회논문지
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• 제29권3C호
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• pp.398-407
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• 2004

본 논문에서는 2차원 웨이블릿 변환을 이용한 영상 압축방식에 적합한 블라인드 워터마킹 방식을 제안하고 VHDL(VHSIC Hardware Description Language)을 이용해서 하드웨어로 구현하였다. 워터마킹 알고리즘의 목적은 영상의 조작에 대해 영상의 무결성을 인증하고 조작이 가해졌을 경우에 조작 위치를 판별하는 것이다. 제안된 워터마크 방식은 동영상 압축 시 적용되는 것으로 가정하였으며, 따라서 양자화에 무관하고 실시간으로 삽입 및 추출이 가능하도록 하였다. 웨이블릿 도메인에서 주파수 특성상 최저파수 대역(LL4)은 공간영역의 변화에 대해 민감하지 않다는 것을 실험적으로 검증하여 LL4를 워터마크의 삽입영역으로 설정하였다. 워터마크 삽입 시 압축된 영상의 화질을 최대한 저하시키지 않으면서 강인성을 지닐 수 있는 비트평면 조합을 LL4 부대역에서 선택하고 이를 워터마크 삽입 포인트로 결정한다. 비트평면에서 워터마크의 삽입위치를 알고 있고 값 변환이 아닌 값의 치환방식으로 워터마크를 삽입하므로 워터마크를 추출할 때에 원 영상이 필요하지 않다. 또한 삽입위치가 노출되었을 때의 안전성을 고려하여 워터마크를 블록암호화 알고리즘을 이용하여 암호화한 후 삽입하도록 하였다. 실험결과 제안된 워터마킹 알고리즘은 일반적인 영상의 조작에 대해 강인성을 보였고 영상 및 비디오 압축기에서 전체 동작과 구조에 큰 변화를 주지 않으면서 이식이 가능하였다. 구현된 영상압축기와 워터마킹 하드웨어는 Altera의 APEX20KC EP20K400CF672-7 FPGA 디바이스에서 약 40%의 LSB를 사용하고 최대 약 60MHz에서 동작이 가능하였다.

• Journal of the Optical Society of Korea
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• 제17권5호
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• pp.362-370
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• 2013

In this paper, we propose a novel optical implementation of a 3DES algorithm based on dual XOR logic operations for a cryptographic system. In the schematic architecture, the optical 3DES system consists of dual XOR logic operations, where XOR logic operation is implemented by using a free-space interconnected optical logic gate method. The main point in the proposed 3DES method is to make a higher secure cryptosystem, which is acquired by encrypting an individual private key separately, and this encrypted private key is used to decrypt the plain text from the cipher text. Schematically, the proposed optical configuration of this cryptosystem can be used for the decryption process as well. The major advantage of this optical method is that vast 2-D data can be processed in parallel very quickly regardless of data size. The proposed scheme can be applied to watermark authentication and can also be applied to the OTP encryption if every different private key is created and used for encryption only once. When a security key has data of $512{\times}256$ pixels in size, our proposed method performs 2,048 DES blocks or 1,024 3DES blocks cipher in this paper. Besides, because the key length is equal to $512{\times}256$ bits, $2^{512{\times}256}$ attempts are required to find the correct key. Numerical simulations show the results to be carried out encryption and decryption successfully with the proposed 3DES algorithm.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제16권3호
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• pp.947-971
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• 2022

The Electronic Medical Record (EMR) is a valuable source of medical data intelligence in e-health systems. The watermarking techniques have been used to authenticate the owner and protect the EMR from illegal copying. The existing distributive strategies, successfully operated to secure the EMR, are found to be inadequate. Blockchain technology, mainly, is employed by a sharing database that allows the digital crypto-currency. It rapidly leads to the magnified expectations acme. In this excitement, the use of consortium adopting the technology based on Blockchain, in the EMR structure, is found improving. This type of consortium adds an immutable share with a translucent record of the entire business and it is accomplished with responsibility, along with faith and transparency. The combination of watermarking and Blockchain technology provides a singular chance to promote a secured, trustworthy electronic documents administration to share with the e-records system. The authors, in this article, present their views on consortium Blockchain technology which is incorporated in the EMR system. The ledger, used for the distribution of the block structure, has team healthcare models based on dissimilar multiple image watermarking techniques.