AUTHORIZED WATERMARKING AND ENCRYPTION SYSTEM BASED ON WAVELET TRANSFORM FOR TELERADIOLOGY SECURITY ISSUES

Transcription

1 AUTHORIZED WATERMARKING AND ENCRYPTION SYSTEM BASED ON WAVELET TRANSFORM FOR TELERADIOLOGY SECURITY ISSUES S.NANDHINI PG SCHOLAR NandhaEngg. College Erode, Tamilnadu, India. Dr.S.KAVITHA M.E.,Ph.d PROFESSOR & DEAN ECE NandhaEngg. College Erode, Tamilnadu, India. ABSTRACT:Teleradiology is the and there is no process repetition. The transmission of radiographic images from software tool to be used is MATLAB. one location to another for interpretation by Keywords:Teleradiology, DWT a radiologist. It is most often used to allow Authentication. rapid interpretation of emergency room, ICU and other emergent examinations after hours I. INTRODUCTION of usual operation, at night and one Teleradiology is the e-health service weekend. Such remote transmission raises to maintain andtransmit medical various ethical and legal issues. In the transcriptions online for the sake of existing methods, dual watermarking system patientsto provide efficient clinical is used for embedding the encrypted patient interpretationwithout carryingthe document details and their fingerprint features for diagnosis purpose. But at present, independently to reduce the maintenance of security andprivacy protection has been a multiple records. In this method initial level critical issue for the patientssuch as image security is not improved and some process is retention and fraud, privacy, malpractice, done repeatedly and hence this increases liability, licensing and contracts for complexity. In the proposed method, radiology information system, picture fingerprint authentication of patient is to be archiving and communication system. done at the initial level which gives the Another major issue is multiple document access on their records. Then watermarking maintenancefor a single patient such as based on DWT is to be done for embedding digital X-ray image, personnel details,and the encrypted patient details and hospital diagnosis results aremaintained and identification. This will increase the security transmitted onlineseparately which needs 83

2 more time to process. It can be avoidedby merging the multiple documents of a single person to a singledocument using watermarking. Teleradiology needs confidentiality,availability, and reliability which means only an authorizeduser can access patient data, guarantee access to medicalinformation in normal scheduled conditions, proves that informationhas not been altered by unauthorized persons, and informationorigins of its attachment relate to one patient. To provideall these aspects, Teleradiology requires watermarking for efficientmaintenance and transmission of medical data remotely. In the paper, both cryptography and watermarking techniques are applied on patient details and medical image for the purpose of secured transmission. The security is improved at the initial level by authenticating the patient fingerprint to access patient reports. The cryptography technique used to encrypt the patient details. Text encryption is achieved by Advanced Encryption Standard (AES). Dual watermarking is done for embedding the hospital identification and for encrypted patient details. The watermarking is achieved by Discrete Wavelet Transform (DWT) technique. The efficiency of output image at the receiver side is analyzed using various parameters like Power Signal to Noise Ratio (PSNR), Entropyand Mean Square Error (MSE). In personnel information system, the confidentiality is usually achieved by fingerprint recognition system which is a widely used biometric system for personnel authentication. At the sender side, the security is improved at the initial level by authenticating the fingerprint of the patient. The fingerprint verification system restricts access of patient data without authentication. The cryptographic system is mainly used in information systems to ensure services like non repudiation, confidentiality, and integrity. To maintain the privacy of the information, symmetric key cryptographic system is used to secure the data. The encryption of the patient details is achieved by AES algorithm. Watermarking improves the security of medical images by modifying or modulating image pixels with a message in an imperceptible way. Dual watermarking is achieved with encrypted patient details and hospital identification based on DWT. Finally the entire watermarked image is encrypted and transmitted to receiver. At the receiver side decryption and dewatermarking is done to obtain the original image and patient details without any loss. Quality of image obtained at the receiver side is verified by various validations like Entropy, MSE, and PSNR. II.DESIGN OF SENDER 84

3 Sender side design involves three different procedures, A.FINGERPRINT AUTHENTICATION Fingerprint recognition system is a widely used biometric system for personnel authentication.among all biometric traits, fingerprints have one of the highest levels of reliability and have been extensively used by forensic experts in criminal investigations. A fingerprint refers to the flow of ridge patterns in the tip of the finger.the ridge flow exhibits anomalies in local regions of the fingertip and it is the position and orientation of these anomalies that are used to represent and match fingerprints is shown in Figure 1. Figure 1: Fingerprint Block diagram of fingerprint authentication system is shown in Figure 2, Figure 2: Fingerprint Authentication system. B. DUAL WATERMARKING In order to improve the security of Teleradiology in terms of confidentiality, availability and reliability dual watermarking approach is done. Dual watermarking is embedding two different data s in the radiology image. One data is hospital identification and the other is encrypted patient details. To improve the security, watermarking is done with a secret key shared with sender and receiver. The two dimensional DWT method is used for watermarking the hospital identification and encrypted patient details. The watermark achieved here is an invisible watermark. Wavelet domain is a promising domain for watermark embedding. Wavelet refers to small waves. Discrete Wavelet Transform is based on small waves of 85

4 limited duration and varying frequency. This is a frequency domain technique in which firstly cover image is transformed into frequency domain and then its frequency coefficients are modified in accordance with the transformed coefficients of the watermark and watermarked image is obtained which is very much robust. DWT decomposes image hierarchically, providing both spatial and frequency description of the image. It decompose an image in basically three spatial directions i.e., horizontal, vertical and diagonal in result separating the image into four different components namely LL, LH, HL and HH. First letter refers to applying either low pass frequency operation or high pass frequency operations to the rows and the second letter refers to the filter applied to the columns of the cover image.two level DWT is shown in Figure 3, Figure 3:Two level DWT 2. Sub-band suitable for embedding watermark is chosen. 3. Wavelet coefficients of the selected sub-band are modified according to the watermark image. 4. After embedding watermark watermarked image is obtained. C. ENCRYPTION This paper merges a digital watermarking algorithm and an encryption algorithm which is a block cipher algorithm (AES). Advanced Encryption Standard (AES) is a very powerful standard block cipher algorithm compared to the data encryption standard (DES) algorithm. The AES is a block cipher, meaning that it operates on an input block of data of a known size and outputs a block of data which is the same size. An input key is also required as input to the AES algorithm. A mode of operation is selected which selects a specific implementation of the AES algorithm. The input blocks and output block data are each a fixed length size of 128 bits. Algorithm for carrying out DWT 1. Original image is decomposed in various sub-bands using DWT, in this paper two- level DWT is use. The AES encryption algorithm involved four stages,these are as follows, 1. Substitute bytes 86

5 3. Mix Columns 2. Shift rows 4. Add Round Key General flow diagram of sender is given in Figure 4, Figure 5: Receiver Flow diagram IV. AUTHORIZED WATERMARKING AND ENCRYPTION SYSTEM A. GUI OF FINGERPRINT AUTHENTICATION: Output of fingerprint authentication is shown in Figure 6 gives access for authorized person on patient records. Figure 4: Sender Flow diagram III. DESIGN FOR RECEIVER The reverse procedure of sender is done at the receiver side. i.edewatermarking and decryption is done. The general flow diagram of receiver is given in Figure 5, Figure 6: GUI for authorized person Output of fingerprint authentication is shown in Figure 7 restricts access for unauthorized person on patient records 87

6 C. GUI OF RECEIVER: Output of Receiver is shown in Figure 9 provides the application of Dewatermark and Decryption to obtain original radiology images. Figure 7: GUI for unauthorized person B.GUI OF SENDER: Output of sender is shown in Figure 8 provides the application of watermark and encryption on radiology images. Figure 9: GUI for Receiver Original patient details and its encrypted form is shown in Figure 10, Figure 8: GUI for sender 88

7 Figure 10: Text and its Encrypted form V. RESULTS AND DISCUSSION Finally on comparing the original image and the decrypted output image obtained at the receiver the image quality is verified in order to evaluate the system efficiency. The image quality metrics obtained is shown in Table 1, S.NO Table 1: Image Quality Metrics METRICS IMAGE1 IMAGE2 FUSED IMAGE 1 ENTROPY confidentiality, integrity and reliability even though it is encrypted. A simulation result shows the secured transmission of image and data with processing time was low. On the other hand, the execution time for image decryption is not impacted. Finally,Image quality obtained at receiver is good. REFERENCES 1. Chen Yunhao, Deng Lei, Li Jing, Li Xiaobing and Shi Peijun (2006), A new wavelet-based image fusion method for remotely sensed data, International Journal of Remote Sensing, Vol. 27, No. 7, pp SF RMSE MAE MEAN PSNR: PSNR > 30.0 (this corresponds to RMSE <8.6) is commonly considered as good VI. CONCLUSION In this paper, a authorized watermarking and encryption system has been proposed, which guarantees an, a priori and a posteriori protection of medical images. It merges the digital watermarking and block cipher algorithm. This system gives access to verify the image 2. Chien-Hsing Chou a, Wen- HsiungLin b, FuChang b,(2010) A Binarization method with learningbuilt rules for document images produced by cameras, Elsevier transaction on Pattern Recognition, Vol 43, pp Hussain.N, Boles.W, Boyd.C (2013), A Review of Medical Image Watermarking requirements for Teleradiology, Journal on Digital Imaging, Vol. 26, No. 2, pp KiranKumar.Y (2009), Comparison of Fusion Techniques Applied to Preclinical Images: Fast Discrete 89

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