The secret image will get visible to the human visual system. Three quadrant method for securing image by using visual. If you are interested in reading more, you can find a reprint of the original paper here. The secret can be visually recovered by stacking k. Colour visual cryptography becomes an interesting research topic after the formal. K out of k extended visual cryptography scheme based on xor. In the k, n visual cryptography scheme, two collections of n x m boolean matrices basis matrices, c0 and c1 are used. Certain subsets of participants, called qualified sets, can visually recover the secret image, but other subsets of participants, called forbidden sets. Visual cryptography is a symmetric key cryptographic technique which allows visual information pictures, text, etc. Using k out of n k, n visual secret sharing scheme a secret image is encrypted in shares which are meaningless images that can be transmitted or distributed over an untrusted communication channel. Probabilistic visual cryptography schemes the computer. Visual cryptography for a set of n participants, a secret image s is encoded into n shadow images called shares each participant gets one share k out of n participants are needed to combine shares and see secret image. Securing online transaction using visual cryptography. S international journal of advanced research in computer and communication engineering, vol.
A visual cryptographic encryption technique for securing. Enhancing multifactor cheating prevention in visual. The beauty of such a scheme is that, the decryption of the secret image requires neither the knowledge of cryptography nor complex computation. In this paper we consider a new type of cryptographic scheme, which can decode concealed images without any cryptographic computations. An efficient kn secret sharing image and aes encryption algorithm in visual cryptography v. The basic idea behind the colored image cryptography remained the same however. In this paper we construct a visual cryptography scheme vcs for the strong access structure specified by the set of all minimal qualified sets, where s. When a white pixel is shared, any one of the matrices out of the collection in c 0 is chosen. A sender wishing to transmit a secret message distributes n transparencies amongst n recipients, where the transparencies contain seemingly random pictures. Visual cryptography is a special encryption technique to hide information in images in such a way that it can be decrypted by the human vision if the correct key image is used. The scheme is perfectly secure and very easy to implement. Visual secret sharing encode secret image s in threshold shadow images shares. In this technique, a secret image of type binary is encoded in a cryptographical manner into random binary patterns which contains n shares in a koutofn scheme.
The n shares are distributed among n participants in such a way the each. Vcs is usually implemented as a threshold k, n scheme, which a secret image is decomposed into n shadow images referred to as shadows and then distributed to n participants. Visual cryptography vc, proposed by naor, is a cryptographic technique based on visual secret sharing used for image encryption. Shares are represented on transparencies secret is reconstructed visually k,n visual threshold scheme k of the shares transparencies are superimposed reveal secret 2,n visual cryptography schemes feng liu 1and chuankun wu 1state key laboratory of information security, institute of software chinese academy of sciences, beijing 100190, china email.
The source image is divided into n number of shares using kn secret sharing visual cryptography scheme such that k number of shares is sufficient to reconstruct the encrypted image. The paper proposed a k out of n c color visual secret sharing system. Visual cryptography scheme vcs is a kind of secretsharing scheme which allows the encryption of a secret image into n shares that are distributed to n participants. Secret sharing also called secret splitting refers to methods for distributing a secret amongst a group of participants, each of whom is allocated a share of the secret. Visual cryptography and k,nvisual secret sharing schemes were introduced by naor and shamir advances in cryptology eurocrypt 94, springer, berlin, 1995, pp. Visual cryptographic technique for enhancing the security. Visual cryptography is a cryptographic technique which allows visual information pictures, text, etc. In addition, the requirement for inputs of the binary or dithered nature only limits the applicability of visual cryptography. In 2, 2 visual cryptography scheme, the original image is.
In this paper we construct a visual cryptography scheme vcs for the strong access structure specified by the set. Visual cryptography free download as powerpoint presentation. The visual cryptographic scheme vcs has been firstly proposed by naor and shamir. Progressive visual cryptography scheme in which we not only build the reconstructed image by stacking the threshold number of shares together, but also utilize the other.
Visual cryptography encodes a secret binary image into n shares of random binary patterns. Figure 4 shows the integration of concept of visual cryptography with pixel index reversal, zigzag scan of the image for a colour image with its integration with n, k, p gray codes. Advances in cryptology eurocrypt 94, lecture notes in computer science volume 950 keywords. Each of the n shares generated in step i is embedded into n number of. The koutofn visual cryptography scheme deals with the secret message as an image consisting of independent white and black pixels. We also obtain bounds for the optimal pixel expansion.
P decryptk, encryptk, p p ok defn to start with, but doesnt include key generation or prob encryption. The secret can be reconstructed only when a sufficient number, of possibly different types, of shares are combined together. Visual cryptography scheme for color image using random. For example, in a k, n visual cryptography scheme, a dealer encodes a secret into n shares and. Any vcs for this strong access structure is called a k, nvcs. Basic concepts in cryptography fiveminute university. Visual cryptography for colored images in 6, it was proposed for the very first time, the use of colored images in visual cryptography. Boolean xor based k,n threshold visual cryptography for. By engaging a cryptographic encryption technique involving. On k, nvisual cryptography scheme, designs, codes and.
The secret image can be visually decoded by superimposing a qualified subset of transparencies, but no secret information can be obtained from the superposition of a forbidden subset 6. A koutofn visual cryptography scheme with parameters 1. Or possibly a subset of any k images out of these n. Multiresolution visualcryptography in traditional k. Image based authentication using visual cryptography and. It could decode the secret handwritten notes, pictures, etc. Pdf secret sharing and authentication using visual. Boolean xor based k, n threshold visual cryptography for grayscale images international journal of computer science and informatics issn print. Any k participants are enabled to reconstruct the secret image by simply stacking together the shadows they own. Each pixel is reproduced as n shares with each share consisting of m subpixels. The technique was proposed by naor and shamir in 1994. Most of the existing secret sharing schemes are generalized within the socalled k,n. As an example, here are some 3 x 3 subelements that could be used to distribute an image over four cypher images, all of which are.
157 382 111 1161 752 679 699 69 466 95 337 1379 635 396 559 434 1005 523 1452 787 619 391 865 390 734 1490 126 1462 1383 1103 1342 1356 215 586