Elsevier

Computer Communications

Volume 152, 15 February 2020, Pages 72-80
Computer Communications

An improved DWT-SVD domain watermarking for medical information security

https://doi.org/10.1016/j.comcom.2020.01.038Get rights and content

Abstract

Exchange of patient record over network required a technique to guarantee security and privacy for tele-health services. This paper presents an improved watermarking technique capable of providing protection of patient data by embedding multi-watermarks in medical cover image using DWT-SVD domain. Prior to embedding, Hamming code is applied to text watermark in order to reduce channel noise distortion for the sensitive data. After embedding, the watermarked medical image is encrypted then compressed. Out of two encryption method and three compression scheme tested, combination of Chaotic-LZW shows the best performance. However, HyperChaotic-LZW combination is more robust against Gaussian, JPEG compression, speckle noise and histogram equalization attacks. We illustrate the good results in terms of objective and subjective evaluation, and verify its robustness for various attacks while maintaining imperceptibility, security and compression ratio. Experimental results demonstrate that the suggested technique archives high robustness against attacks in comparison to the other scheme for medical images.

Introduction

Security and privacy of medical information are mostly presented as major issue in teleHealth services [1]. The teleHealth services uses advanced cost effective information and communication technology (ICT) tools to manage, store and transmit medical record for various purpose [2]. These services are convenient and potentially useful in medical domain but also bring a privacy leakage, identity theft and risk of data tampering and authenticity at the same time [3]. Further, digital imaging and communications in medicine (DICOM) is used as standard to exchange the electronic patient report over open network [4]. A header file is attached with DICOM image which contains significant patient related information. However, this header consumes extra bandwidth and may be altered, removed or attacked during the transmission. Furthermore, medical related identity theft is booming problem as demonstrated by various surveys [3], [5]. According to a survey conducted by Experian Information Solutions in 2017, medical thefts constitute more than 27% of the total identity thefts [5]. The stolen information affects the individual life to a great extent. Therefore, there is a need for strong mechanisms to be proposed which resolves the security and privacy issue of medical information for teleHealth services. Recently, digital watermarking techniques have attracted remarkable interest for protection of medical data [3], [6]. The technique refers the embedding of confidential information in a media/entity for determining any ownership conflicts that can arise [3], [7]. Some potential applications of digital watermarking are depicted in Fig. 1 [6], [8], [9].

Currently, encryption and watermarking approaches are used to provide authenticity and confidentiality of medical record [10], [11], [12], [13]. The watermarked media being transmitted might get some unwanted channel noises or get attacked upon. This makes the technique less robust resulting in receiving distorted media. So the concept of encryption is combined with watermarking to make the technique anti-attack in nature [14], [15]. Encryption deals with the secure transmission of the data over an insecure transmission media [16].

In order to this, many researchers used combined (Encryption-Watermarking) approach to address the security issues of teleHealth applications [4], [10], [11], [12], [13]. However, few studied of watermarking-encryption-compression concepts for the applications [14], [17]. In this paper, we developed an improved dual watermarking approach that uses combination of DWT-SVD, Encryption-compression and hamming code to provide security for medical information exchanged via unsecured networks. The approach uses multi-watermarks embedded into SVD of cover image in DWT domain. The DWT has great spatio-frequency properties which help in recognizing the area where the watermark can be embedded with high imperceptibility. Also, embedding in the singular matrix of SVD does not have noticeable change in the visual quality of the cover image. Thus, using a hybrid of DWT and SVD helps in achieving higher robustness and imperceptibility [4]. An encoded text watermark via hamming code is also embedded in the higher level DWT to provide more security. Additionally, the watermarked image is first encrypted then compressed prior transmission to achieve extra security and reduce the bandwidth demand. Therefore, the major advantages the of our technique are (1) Robustness and imperceptibility is increased by using hybrid transform (DWT-SVD) at low distortion, (2) Providing extra level of security by embedding multiple watermarks, (3) Encryption of the marked image is providing confidentiality at the same time, and (4) Compression of encrypted data shown the good compression performance.

Rest of the paper is organized as follows. Recent work related to teleHealth applications is introduced in Section 2. Section 3 describes the more important concepts related to our work. The embedding and recovery part of our method is elaborated in Section 4. Section 5 presents the performance analysis of the work. Finally, conclusions are drawn in Section 6.

Section snippets

Literature review

Some of the related work is proposed in literature survey are discuss below.

Least Significant Bit (LSB) based data hiding scheme for colored medical images is introduced by Boonyapalanant et al. in [18] in which QR code containing the entire patient’s data is used as watermark. The embedding of the watermark is distributed over the whole image and does not affect the image size. It is experimentally proved that this technique is robust against rotational attacks. A blind, robust and zero

Discrete wavelet transforms (DWT)

The DWT is used to decompose the image into non-overlapping sub-bands, namely, approximation (LL), horizontal (LH), vertical (HL) and diagonal (HH). We can further decompose the ‘LL’/or other sub-band to obtain wavelet coefficients at multiple level (see Fig. 2). Multi-resolution property of DWT helps in easily locating the areas in the cover image where the watermark should be embedded [3]. Above mentioned properties makes DWT suitable for medical image watermarking [4], [11], [22], [23]. It

Proposed method

The proposed method consists of mainly three parts i.e. embedding, transmission and extraction of the watermarks. Before the embedding process, the text watermark is encoded using Hamming code and the image watermark is divided into two sub images. Cover image is then decomposed at second level DWT. Singular component of intermediate frequency sub-bands i.e. ‘HL’ and ‘LH’, of the first level DWT coefficients are embedded with the two sub-parts of the medical watermark images. Further, the

Result and analysis

We conducted experiments on hundred different medical cover images (size: 512 ×  512) [46], watermark data: image of size 256 ×  256 and text of size up to 12 characters, using MATLAB R2017a. Additionally, “Ashima NIT01” is taken as text watermark. Fig. 7 presents the some samples of our images and text data. The objective and subjective method [3] are used to determine the performance of our approach. The detail description of all considered standard metric (objective measures) is provided in

Conclusion

In this paper, an improved non-blind, robust, imperceptible and secure watermarking technique is developed for concealing multi-watermarks using DWT-SVD with hamming code. To reduce the possibility of channel noise, the text watermark is encoded with hamming code prior to concealing into the cover image. By applying the concepts of encryption-compression on watermarked image, the confidentiality and compression performance of the proposed method is improved. The result demonstration has shown

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

The authors thanks the potential reviewer’s for their constructive comments and suggestions that greatly contributed to improving this article.

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