A new two-level information protection scheme based on visual cryptography and QR code with multiple decryptions
یک برنامه محافظت از اطلاعات دو سطح جدید مبتنی بر رمزنگاری بصری و کد QR با رمزگشایی های متعدد-2019
Nowadays, Quick Response (QR) code has been used in many fields due to its advantages, such as reliability, high-speed scanning and large data capacity. However, embedding the privacy information into the QR code lacks adequate security protection. In this paper, a new two-level information protection scheme is designed based on visual cryptography and QR code. Using any standard QR reader device or software, the public-level information can be read out directly from the shares. Moreover, the privacy-level information can be decoded by three different decryptions, which are suitable to non-computation with relative difference 1/4, lightweight computation with relative difference 1/2 and common computation environments with relative difference 1, respectively. Since the proposed scheme keeps the advantages of visual cryptography and QR code, it differs from the related schemes with low computational complexity, robustness against deformations, and high payload. The effectiveness of the proposed scheme has been proved theoretically. Experimental results and analysis demonstrate that the proposed scheme can protect two-level information with multiple decryptions, and has many benefits compared with the previous schemes.
Keywords: Two-level information protection | Visual cryptography | QR code | Multiple decryptions
A general progressive secret image sharing construction method
یک روش ساخت و ساز به اشتراک گذاری تصویر مخفی پیشرو-2019
Classic secret image sharing (SIS) including polynomial-based SIS, visual secret sharing (VSS), linear congruence (LC)-based SIS and so on, generally has the shortcoming of ‘‘all-or-nothing’’, which is mainly caused by that most of their ideas are borrowed from secret data sharing designed for data rather than image. Progressive secret image sharing (PSIS) has the feature that the more shadows the better recovered secret image quality. In this paper, we introduce a general PSIS construction method with no pixel expansion from classic ‘‘all-or-nothing’’ SIS. Based on our PSIS construction method, three PSIS algorithms with selective progressive thresholds are extended from classic SIS schemes, respectively. Experiments are provided to demonstrate the efficiency of our method in terms of illustrations and analyses.
Keywords: Secret image sharing | Progressive secret image sharing | Polynomial-based secret image sharing | Visual cryptography | Linear congruence
Random grid based color visual cryptography scheme for black and white secret images with general access structures
طرح رمزنگاری بصری مبتنی بر شبکه تصادفی برای تصاویر مخفی سیاه و سفید با ساختارهای دسترسی عمومی-2019
To reduce the pixel expansion problem in color–black-and-white visual cryptography schemes (CBW-VCSs) and to provide flexible sharing strategy simultaneously, a random grid based CBW-VCS (RG-CBW-VCS) for general access structure (GAS) is proposed in this paper. First of all, the concept of random grid is extended to color pixel domain, and the XOR operation for color pixels is defined. By adopting this operation, a scheme for RGCBW- VCS which implements the GAS is introduced. The proposed method is further extended to realize the generalized GAS (GGAS), where implementing complicated sharing strategy becomes available. Theoretical analysis on the proposed method are given to prove the security and contrast conditions, as well as the calculation of contrast. Experimental results are exhibited to show that optimal pixel expansion is achieved by the proposed method.
Keywords: Visual cryptography | Random grid | General access structure | Color | Black and white | Pixel expansion
A ( k , n ) Threshold Partial Reversible AMBTC-based Visual Cryptography Using One Reference Image
A (k ، n) رمزنگاری تصویری مبتنی بر AMBTC قابل برگشت جزئی با استفاده از یک تصویر مرجع-2019
Recently, Yang et al. introduced a ðk; nÞ approach called Reversible Absolute moment block truncation coding Visual Cryptography Scheme (RAVCS) (Yang et al., 2017) to conceal a secret image into n AMBTC shares. However, a large number of reference images is used in their method. To reduce the number of reference images, a ðk; nÞ PRAVCS using one AMBTC reference image is introduced. In encoding phase, a binary secret image is shared into n AMBTC shadow images according to the base matrices generated by two proposed constructions. In decoding phase, the secret image is recovered by stacking sufficient bitmaps, and the AMBTC reference image is partially recovered as well. When n AMBTC shares are used, losslessly reconstruction for the reference image is obtained. Theoretical analysis and experiments by the proposed method are demonstrated to show the effectiveness. Moreover, Construction 1 has larger contrast, while Construction 2 achieves higher reversibility for more thresholds.
Keywords: Visual cryptography | Block truncation coding | Partial reversible | Meaningful share | Contrast | Reference image
A combination of color-black-and-white visual cryptography and polynomial based secret image sharing
ترکیبی از رمزنگاری بصری رنگی سیاه و سفید و اشتراک گذاری مخفی مبتنی بر چند جمله ای-2019
A new ðk; nÞ threshold secret image sharing scheme with two decoding options is introduced in this paper. The proposed scheme combines color-black-and-white visual cryptography scheme (CBW-VCS) and polynomial based secret image sharing (PSIS) together, to offer stacking-to-see decryption and lossless image reconstruction. To construct the color shares, a general ðk; nÞ threshold CBW-VCS is firstly given. A grayscale secret image is converted to a p-radix image and a binary image. The p-radix image is encrypted by the ðk; nÞ PSIS under mod p operation, and n p-radix shadows are obtained. Then, a color share generation algorithm with data embedding is proposed to construct n color shares. Theoretical analysis and sufficient experiments are provided to show the effectiveness and advantages of the proposed scheme.
Keywords: Visual cryptography | Secret image sharing | Color | Embedding | Polynomial | Black and white
A (2,2) XOR-based visual cryptography scheme without pixel expansion
(2،2) طرح رمزنگاری بصری مبتنی بر XOR بدون گسترش پیکسل-2019
Visual cryptography (VC) is a technique that encodes the content of a secret image into two or more images, which are called shares. These shares are printed on transparencies and superimposed to reveal the original secret image. Frequently, VC techniques require a pixel expansion and a good alignment, which reduces the final spatial resolution. In this paper, we propose a physical VC scheme that only requires two shares and do not demand a pixel expansion. The first share is a colored transparency printed on a Polyvinyl Chloride (PVC) surface of 3 mm, while the second share is a colored image displayed on a smartphone screen. The decoded pixels of the proposed scheme have defined colors and a good resolution. We perform a physical evaluation of the color interference properties of the two shares, to find the most adequate color space, and test the proposed method with practical examples.
Keywords: Visual cryptography | Visual secret sharing | Color interference
A new efficient TKHC-based image sharing scheme over unsecured channel
یک طرح به اشتراک گذاری تصویر کارآمد مبتنی بر TKHC بر روی کانال نا امن-2019
The major problems of Visual Secret Sharing (VSS) are the pixel expansion and lossy recovery. The former creates large-sized shared images and makes their handling, storage, and speed transmission via networks challenging, whereas the latter leads to poor contrast of the recovered images. In addition, sharing a huge volume of images and transmitting the shared images through one less channel is a critical problem of VSS where any unauthenticated user can attack, discover the generated shares, and recover the secret image. In this paper, an efficient TKHC algorithm is proposed to augment the privacy and safety of the shared images. Moreover, the new TKHC-based VSS scheme is utilized to sharing a huge RGB and grayscale images which are subjected to be encrypted and decrypted by means of TKHC and providing strong security to transmit all the generated shares via one public channel. In comparison to the existing schemes, the proposed scheme shows significant improvement in encryption quality with lightweight computation cost. Furthermore, it withstands the known-plaintext and brute-force attacks and overall creates a balance between security, cost, and performance.
Keywords: Visual cryptography (VC) | Secret sharing | Hill Cipher | Confidentiality | Histogram | Pixels correla
Secure telemedicine using RONI halftoned visual cryptography without pixel expansion
تله پزشکی امن با استفاده از رمزنگاری بصری نیمه تمام RONI بدون گسترش پیکسل-2019
To provide quality healthcare services worldwide telemedicine is a well-known technique. It delivers healthcare services remotely. For the diagnosis of disease and prescription by the doctor, lots of infor- mation is needed to be shared over public and private channels. Medical information like MRI, X-Ray, CT-scan etc. contains very personal information and needs to be secured. Security like confidentiality, privacy, and integrity of medical data is still a challenge. It is observed that the existing security tech- niques like digital watermarking, encryption are not efficient for real-time use. This paper investigates the problem and provides the solution of security considering major aspects, using Visual Cryptography (VC). The proposed algorithm creates shares for parts of the image which does not have relevant infor- mation. All the information which contains data related to the disease is supposed to be relevant and is marked as the region of interest (ROI). The integrity of the image is maintained by inserting some information in the region of non-interest (RONI). All the shares generated are transmitted over different channels and embedded information is decrypted by overlapping (in XOR fashion) shares in θ(1) time. Visual perception of all the results discussed in this article is very clear. The proposed algorithm has per- formance metrics as PSNR (peak signal-to-noise ratio), SSIM (structure similarity matrix), and Accuracy having values 22.9452, 0.9701, and 99.8740 respectively.
Keywords: Error diffusion | Halftone | RONI | Telemedicine | Visual cryptography
A highly robust and secure image watermarking based on classification and visual cryptography
علامت تصویری بسیار مستحکم و مطمئن بر اساس طبقه بندی و رمزنگاری بصری-2019
In this paper a new robust image watermarking algorithm based on blocks classification and visual cryp- tography (VC) is presented. First the original image is decomposed into non-overlapping blocks. Then, we use canny edge detection and the support vector machine (SVM) classification method to categorize these blocks into smooth and non-smooth classes. The VC technique is used to generate two image shares: A master share that is constructed according to the block classification results and an owner share gener- ated by using the master share together with a binary watermark. To verify the ownership of the image, the watermark can be retrieved by stacking the master share and the owner share. By skipping blocks which are not robust against attacks, the robustness of our proposed watermarking method is signifi- cantly improved. Our method is completely imperceptible because the watermark pattern is concealed without modifying the original host image.
Keywords: Image watermarking | Visual cryptography | Image blocks classification | Support vector machine | Robust blocks
High-capacity encryption system based on single-shot-ptychography encoding and QR code
سیستم رمزگذاری ظرفیت بالا مبتنی بر رمزگذاری تک شات و رمزگذاری کد QR-2019
We proposed a high-capacity optical encryption system based on single-shot-ptychography encoding (SPE) technique and quick response (QR) code. Two QR codes are utilized as date containers, one of which is encoded into random binary images (one is encoded image, another one is key) through visual cryptography (VC). Finally, the encoded images are encrypted by single-shot-ptychography encoding technology. It increases the variety of system-keys and overcomes the disadvantages of encrypting only binary images in SPE encoding systems. The security of the proposed system is mainly supported by VC extension encoding. The result of recovery does not have any distortion compared to the original plaintext. Simulation results show that this system has large-capacity information storage, powerful error correction capability, higher security and robustness.
Keywords: QR code | Single-shot-ptychography | Visual cryptography