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This paper proposes a replacement system of foolproof examination by tamperproof e-question paper preparation and secure transmission using secret sharing scheme. The appliance is perfectly secure because the proposed method automatically embeds the corresponding institute lock in the shape of the key. As a result, it's easy to trace out the source culprit for the leakage of question papers. This scheme has reduced reconstruction time because the reconstruction process involves only Exclusive-OR (XOR) operation aside from authentication. The proposed method recovers the first secret image with none loss. The prevailing visual cryptographic scheme recovers half-toned secret image with average Peak signal-to-noise (PSNR) value 24dB. Further, it shall be stated that the proposed method with authentication recovers the image with 64.7dB PSNR value, which is bigger than that of the prevailing method. Additionally, this method doesn't suffer from pixel Expansion.

This paper proposes a replacement system of foolproof examination by tamperproof e-question paper preparation and secure transmission using secret sharing scheme. The appliance is perfectly secure because the proposed method automatically embeds the corresponding institute lock in the shape of the key. As a result, it's easy to trace out the source culprit for the leakage of question papers. This scheme has reduced reconstruction time because the reconstruction process involves only Exclusive-OR (XOR) operation aside from authentication. The proposed method recovers the first secret image with none loss. The prevailing visual cryptographic scheme recovers half-toned secret image with average Peak signal-to-noise (PSNR) value 24dB. Further, it shall be stated that the proposed method with authentication recovers the image with 64.7dB PSNR value, which is bigger than that of the prevailing method. Additionally, this method doesn't suffer from pixel Expansion.

This paper proposes a replacement system of foolproof examination by tamperproof e-question paper preparation and secure transmission using secret sharing scheme. The appliance is perfectly secure because the proposed method automatically embeds the corresponding institute lock in the shape of the key. As a result, it's easy to trace out the source culprit for the leakage of question papers. This scheme has reduced reconstruction time because the reconstruction process involves only Exclusive-OR (XOR) operation aside from authentication. The proposed method recovers the first secret image with none loss. The prevailing visual cryptographic scheme recovers half-toned secret image with average Peak signal-to-noise (PSNR) value 24dB. Further, it shall be stated that the proposed method with authentication recovers the image with 64.7dB PSNR value, which is bigger than that of the prevailing method. Additionally, this method doesn't suffer from pixel Expansion.

This paper proposes a replacement system of foolproof examination by tamperproof e-question paper preparation and secure transmission using secret sharing scheme. The appliance is perfectly secure because the proposed method automatically embeds the corresponding institute lock in the shape of the key. As a result, it's easy to trace out the source culprit for the leakage of question papers. This scheme has reduced reconstruction time because the reconstruction process involves only Exclusive-OR (XOR) operation aside from authentication. The proposed method recovers the first secret image with none loss. The prevailing visual cryptographic scheme recovers half-toned secret image with average Peak signal-to-noise (PSNR) value 24dB. Further, it shall be stated that the proposed method with authentication recovers the image with 64.7dB PSNR value, which is bigger than that of the prevailing method. Additionally, this method doesn't suffer from pixel Expansion.

This paper proposes a replacement system of foolproof examination by tamperproof e-question paper preparation and secure transmission using secret sharing scheme. The appliance is perfectly secure because the proposed method automatically embeds the corresponding institute lock in the shape of the key. As a result, it's easy to trace out the source culprit for the leakage of question papers. This scheme has reduced reconstruction time because the reconstruction process involves only Exclusive-OR (XOR) operation aside from authentication. The proposed method recovers the first secret image with none loss. The prevailing visual cryptographic scheme recovers half-toned secret image with average Peak signal-to-noise (PSNR) value 24dB. Further, it shall be stated that the proposed method with authentication recovers the image with 64.7dB PSNR value, which is bigger than that of the prevailing method. Additionally, this method doesn't suffer from pixel Expansion.

This paper proposes a replacement system of foolproof examination by tamperproof e-question paper preparation and secure transmission using secret sharing scheme. The appliance is perfectly secure because the proposed method automatically embeds the corresponding institute lock in the shape of the key. As a result, it's easy to trace out the source culprit for the leakage of question papers. This scheme has reduced reconstruction time because the reconstruction process involves only Exclusive-OR (XOR) operation aside from authentication. The proposed method recovers the first secret image with none loss. The prevailing visual cryptographic scheme recovers half-toned secret image with average Peak signal-to-noise (PSNR) value 24dB. Further, it shall be stated that the proposed method with authentication recovers the image with 64.7dB PSNR value, which is bigger than that of the prevailing method. Additionally, this method doesn't suffer from pixel Expansion.

This paper proposes a replacement system of foolproof examination by tamperproof e-question paper preparation and secure transmission using secret sharing scheme. The appliance is perfectly secure because the proposed method automatically embeds the corresponding institute lock in the shape of the key. As a result, it's easy to trace out the source culprit for the leakage of question papers. This scheme has reduced reconstruction time because the reconstruction process involves only Exclusive-OR (XOR) operation aside from authentication. The proposed method recovers the first secret image with none loss. The prevailing visual cryptographic scheme recovers half-toned secret image with average Peak signal-to-noise (PSNR) value 24dB. Further, it shall be stated that the proposed method with authentication recovers the image with 64.7dB PSNR value, which is bigger than that of the prevailing method. Additionally, this method doesn't suffer from pixel Expansion.

This paper proposes a replacement system of foolproof examination by tamperproof e-question paper preparation and secure transmission using secret sharing scheme. The appliance is perfectly secure because the proposed method automatically embeds the corresponding institute lock in the shape of the key. As a result, it's easy to trace out the source culprit for the leakage of question papers. This scheme has reduced reconstruction time because the reconstruction process involves only Exclusive-OR (XOR) operation aside from authentication. The proposed method recovers the first secret image with none loss. The prevailing visual cryptographic scheme recovers half-toned secret image with average Peak signal-to-noise (PSNR) value 24dB. Further, it shall be stated that the proposed method with authentication recovers the image with 64.7dB PSNR value, which is bigger than that of the prevailing method. Additionally, this method doesn't suffer from pixel Expansion.

Securing of medical images against intentional or accidental modification is a general issue in modern radiology. Watermarking, with its data-centric security, is very convenient for this purpose. We proposed a new method of fully reversible watermarking in medical imaging by combining the advantages of three traditional approaches - Reversible, Zero and RONI watermarking. The new method achieves exceptionally high values of Peak Signal to Noise Ratio and Structural Similarity index. The article evaluates the pros and cons of current methods of watermarking in medical imaging. Keeping the pros and eliminating the cons of the methods allows a new approach. Specific methods are selected and their application in practice described in detail. Application of the proposed method on a database of 6000 medical images from common hospital operations delivers very promising results which are discussed at the end of the article.

Securing of medical images against intentional or accidental modification is a general issue in modern radiology. Watermarking, with its data-centric security, is very convenient for this purpose. We proposed a new method of fully reversible watermarking in medical imaging by combining the advantages of three traditional approaches - Reversible, Zero and RONI watermarking. The new method achieves exceptionally high values of Peak Signal to Noise Ratio and Structural Similarity index. The article evaluates the pros and cons of current methods of watermarking in medical imaging. Keeping the pros and eliminating the cons of the methods allows a new approach. Specific methods are selected and their application in practice described in detail. Application of the proposed method on a database of 6000 medical images from common hospital operations delivers very promising results which are discussed at the end of the article.

Securing of medical images against intentional or accidental modification is a general issue in modern radiology. Watermarking, with its data-centric security, is very convenient for this purpose. We proposed a new method of fully reversible watermarking in medical imaging by combining the advantages of three traditional approaches - Reversible, Zero and RONI watermarking. The new method achieves exceptionally high values of Peak Signal to Noise Ratio and Structural Similarity index. The article evaluates the pros and cons of current methods of watermarking in medical imaging. Keeping the pros and eliminating the cons of the methods allows a new approach. Specific methods are selected and their application in practice described in detail. Application of the proposed method on a database of 6000 medical images from common hospital operations delivers very promising results which are discussed at the end of the article.

Securing of medical images against intentional or accidental modification is a general issue in modern radiology. Watermarking, with its data-centric security, is very convenient for this purpose. We proposed a new method of fully reversible watermarking in medical imaging by combining the advantages of three traditional approaches - Reversible, Zero and RONI watermarking. The new method achieves exceptionally high values of Peak Signal to Noise Ratio and Structural Similarity index. The article evaluates the pros and cons of current methods of watermarking in medical imaging. Keeping the pros and eliminating the cons of the methods allows a new approach. Specific methods are selected and their application in practice described in detail. Application of the proposed method on a database of 6000 medical images from common hospital operations delivers very promising results which are discussed at the end of the article.

Securing of medical images against intentional or accidental modification is a general issue in modern radiology. Watermarking, with its data-centric security, is very convenient for this purpose. We proposed a new method of fully reversible watermarking in medical imaging by combining the advantages of three traditional approaches - Reversible, Zero and RONI watermarking. The new method achieves exceptionally high values of Peak Signal to Noise Ratio and Structural Similarity index. The article evaluates the pros and cons of current methods of watermarking in medical imaging. Keeping the pros and eliminating the cons of the methods allows a new approach. Specific methods are selected and their application in practice described in detail. Application of the proposed method on a database of 6000 medical images from common hospital operations delivers very promising results which are discussed at the end of the article.

Securing of medical images against intentional or accidental modification is a general issue in modern radiology. Watermarking, with its data-centric security, is very convenient for this purpose. We proposed a new method of fully reversible watermarking in medical imaging by combining the advantages of three traditional approaches - Reversible, Zero and RONI watermarking. The new method achieves exceptionally high values of Peak Signal to Noise Ratio and Structural Similarity index. The article evaluates the pros and cons of current methods of watermarking in medical imaging. Keeping the pros and eliminating the cons of the methods allows a new approach. Specific methods are selected and their application in practice described in detail. Application of the proposed method on a database of 6000 medical images from common hospital operations delivers very promising results which are discussed at the end of the article.

Error Diffusion has been widely adopted in the printing industry due to its good visual quality and simple implementation. However, error diffusion still possesses its own deficiencies. Thus multiscale error diffusion (MED) has been developed, and this method outperforms traditional error diffusion according to extensive research results. The majority of previous halftone image watermarking techniques cannot be directly applied to MED halftone images. Since there is no halftone visual watermarking (HVW) method for MED halftone images in existing methods, the authors propose the first HVW method for MED halftone images, Copyright Protecting Multiscale Error Diffusion (CoP-MED), in this paper. By adopting the visual cryptography principle, CoP-MED can effectively embed a secret pattern into two MED halftone images, where the secret pattern can be decoded clearly by simply overlaying the two stego halftone images or performing not-exclusive-or operation between them. Parameter selection is also discussed based on the experimental results. Later, in comparison tests, CoP-MED shows superior performance compared to existing works. Copyright © 2015, IGI Global.

Error Diffusion has been widely adopted in the printing industry due to its good visual quality and simple implementation. However, error diffusion still possesses its own deficiencies. Thus multiscale error diffusion (MED) has been developed, and this method outperforms traditional error diffusion according to extensive research results. The majority of previous halftone image watermarking techniques cannot be directly applied to MED halftone images. Since there is no halftone visual watermarking (HVW) method for MED halftone images in existing methods, the authors propose the first HVW method for MED halftone images, Copyright Protecting Multiscale Error Diffusion (CoP-MED), in this paper. By adopting the visual cryptography principle, CoP-MED can effectively embed a secret pattern into two MED halftone images, where the secret pattern can be decoded clearly by simply overlaying the two stego halftone images or performing not-exclusive-or operation between them. Parameter selection is also discussed based on the experimental results. Later, in comparison tests, CoP-MED shows superior performance compared to existing works. Copyright © 2015, IGI Global.

Error Diffusion has been widely adopted in the printing industry due to its good visual quality and simple implementation. However, error diffusion still possesses its own deficiencies. Thus multiscale error diffusion (MED) has been developed, and this method outperforms traditional error diffusion according to extensive research results. The majority of previous halftone image watermarking techniques cannot be directly applied to MED halftone images. Since there is no halftone visual watermarking (HVW) method for MED halftone images in existing methods, the authors propose the first HVW method for MED halftone images, Copyright Protecting Multiscale Error Diffusion (CoP-MED), in this paper. By adopting the visual cryptography principle, CoP-MED can effectively embed a secret pattern into two MED halftone images, where the secret pattern can be decoded clearly by simply overlaying the two stego halftone images or performing not-exclusive-or operation between them. Parameter selection is also discussed based on the experimental results. Later, in comparison tests, CoP-MED shows superior performance compared to existing works. Copyright © 2015, IGI Global.

We propose to use cellular automata of dimension 2 as graphic cryptosystems. In particular, a 256-coloured graphic cryptosystem is analyzed. Moreover, the security of the cryptosystem is studied and it is proved that it is safe against brute force and chosen-plaintext attacks. The cryptosystem can easily be extended for images defined by pixels with a different number of colours.

Visual cryptography, introduced by Naor-Shamir at Eurocrypt '94, only requires primitive technology to decrypt the ciphertext. However, a disadvantage of it is that the "ciphertext", as a random looking transparency, is suspicious to a censor. The solutions recently proposed by Desmedt-Hou-Quisquater to avoid these problems are neither user friendly, having a low bandwidth, nor are tested. In this paper we present three schemes that overcome these problems. As in one of the Desmedt-Hou-Quisquater's schemes, a share (or a ciphertext) corresponds to an audio signal, such as music. While in the Desmedt-Hou-Quisquater scheme the plaintext was binary, in our schemes the plaintext can also be speech, or any other audio signal. By introducing variations of the one-time pad we guarantee perfect secrecy. The ciphertext is nonsuspicious, when tested with human ears, is indistinguishable from normal music.